All Java Related Technologies and Tutorials

Java FX For All! - Experiences:

2009-05-20T17:43:00.002-07:00

I also added JavaFX and J2ME Controller as part of
the Project.
To say truely,Learning and Programming Java FX IS SIMPLER,EASIER.
I request every one to do this!!!

Proposal Document

2009-05-20T17:43:00.001-07:00

Proposal for the Code Java FX Contest

Title: Java™ FX for All

What is unique about this application?

The Java™ Media Framework does not support playing of videos with FLV Format. The Java FX Technology enables easy playing of FLV Videos. Also the application we have developed will enable vision challenged people to use it in an easy manner with out others help.

Which aspects of Java FX Technology are you going to use in your application?
We have used Java FX Media Player Component. The aspect we have used in our application is Graphics, Animations and Media.

Description:

After launching the application you will see you see a splash screen with some animated effects. Then you will see many applications embedded on a tab. We enable easy use of the system by the vision challenged people. This application we have chosen is suitable for all sorts of people. We may also make this application to speak aloud the contents in the web pages.

The Application first we have added in the tab is text to speech converter. This application conveys the messages from the system to Vision challenged people through Voice.

The Application will open the CD Tray with out touching the eject button on the CD Tray. We have used this under Windows Platform. If the application is required to be run under the Operating System other than windows we have to make a little change in this part.

The Application will have access to system resources (EX) Notepad in case of Windows Operating System. This application will create process automatically without human interface.

The application enables to display images either in local file system or in the web server.

Actually with notepad (Windows) we may create only text documents. In our application we have created a multi - pad that will create Text Documents, PDF – Portable Document Format Files, Audio Files (.wav, .mp3), Video Files (.mov), Image Files( JPEG,GIF,BMP).

Another application will simulate what the Print Screen button in our key board does. It will capture the entire desktop as image. Then with Key board we can control the mouse.

The application will get and set the Monitor Screen Attributes such as width, height, refresh rate etc.

The application we have designed will control the entire System (both hardware and software) with Voice. Based on the commands you speak in the microphone, appropriate applications will be launched.

At last we have designed an application that will collect the entire information about the Operating System under which the Java FX is currently running.

Java FX For All!!

2009-05-20T17:32:00.000-07:00

Well, I was a Participant of the Code JavaFX Contest.
I would like to share some details about my Project.

The following was my Project Proposal:
Proposal for the Code Java FX Contest
Title: Java™ FX for All
What is unique about this application?

The Java™ Media Framework does not support playing of videos
with FLV Format.
The Java FX Technology enables easy playing of FLV Videos. Also the
application we have developed will enable vision challenged people to
use it in an easy manner with out others help.

Which aspects of Java FX Technology are you going to use in your application?

We have used Java FX Media Player Component. The aspect we
have used in our application is Graphics, Animations and Media.

Description:

After launching the application you will see you see a
splash screen with some animated effects. Then you will see many
applications embedded on a tab. We enable easy use of the system by
the vision challenged people. This application we have chosen is
suitable for all sorts of people. We may also make this application to
speak aloud the contents in the web pages.

The Application first we have added in the tab is text to
speech converter. This application conveys the messages from the
system to Vision challenged people through Voice.

The Application will open the CD Tray with out touching the
eject button on the CD Tray. We have used this under Windows Platform.
If the application is required to be run under the Operating System
other than windows we have to make a little change in this part.

The Application will have access to system resources (EX)
Notepad in case of Windows Operating System. This application will
create process automatically without human interface.

The application enables to display images either in local
file system or in the web server. Actually with notepad (Windows) we
may create only text documents. In our application we have created a
multi - pad that will create Text Documents, PDF – Portable Document
Format Files, Audio Files (.wav, .mp3), Video Files (.mov), Image
Files( JPEG,GIF,BMP).

Another application will simulate what the Print Screen
button in our key board does. It will capture the entire desktop as
image. Then with Key board we can control the mouse.The application
will get and set the Monitor Screen Attributes such as width, height,
refresh rate etc.

The application we have designed will control the entire
System (both hardware and software) with Voice. Based on the commands
you speak in the microphone, appropriate applications will be
launched.

At last we have designed an application that will
collect the entire information about the Operating System under which
the Java FX is currently running.

Open Source Fedora

2009-04-15T05:36:00.001-07:00

A Latest Technical Article for
TechRepublic.com
Here it is!!!
http://blogs.techrepublic.com.com/opensource/?p=542&tag=nl.e011

Java Update Released!!

2009-03-08T06:45:00.000-07:00

Want to use the power full open source Java ™ Technology?
Java update 12 for JDK Released.
Get it here http://www.java.sun.com/downloads
Java is Found every where..
In your Mobile Phones,PDA - Personal Digital Assistant, Blue Ray Disk, Computer...
Java™ Rocks!!
Can u imagine a world with out Java!!!
Never..
Thanks for James Gosling..
For giving this powerful Language....
A Special Dedication for James Gosling..

FireFox 2.0.4 Code

2009-03-08T06:41:00.000-07:00

Are you a great admirer of Open Source.?
Want to see the Source Code of rocking Firefox?
Its Open Source!!!!
You Get it here
ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/2.0.0.4/source/firefox-2.0.0.4-source.tar.bz2

Java FX Released

2009-03-08T06:39:00.000-07:00

Read latest Java™ FX updates here
http://www.javafx.com

FireFox 3.0.7

2009-03-08T06:38:00.000-07:00

Firefox 3.0.7 Released!!!!!
Want to Download Firefox 3.0.7?
Get it here
http://www.mozilla.com/products/download.html?product=firefox-3.0.7&os=win&lang=en-US

Get AVG Here

2009-01-13T18:16:00.000-08:00

http://software-files.download.com/sd/_0PHINY0qH88ez5vKKo-4S7vkon843Af2CWfRYKPz4Yi8oZAe2BvfIQtjD7HB5Odu5PEBHBxDV8IaIED14PKJZAC_IzYjtM4/software/10997344/10710160/3/avg_ipw_stf_en_8_229a1410.exe?lop=link&ptype=1901&ontid=2239&siteId=4&edId=3&spi=228c0fbe4600cef70879e15350ff1857&pid=10997344&psid=10710160

Get Java BioInformatics E Book Here

2009-01-13T17:19:00.000-08:00

http://rapidshare.com/files/23711747/Java.for.Bioinformatics.and.Biomedical.Applications-0387372350.pdf

Get ASP.Net E Book Here.

2009-01-13T17:13:00.000-08:00

http://free-file-hosting.info/showfile-113/ebook_asp_net_3_5_beginners_guide.zip

Get Professional ASP.NET 2.0 AJAX.chm here

2009-01-13T16:58:00.000-08:00

http://download272.mediafire.com/dtvb0saxsl2g/etp4mxjmvdg/www.free-ebooks-download.org----Professional+ASP.NET+2.0+AJAX.chm

Know some basics about CDC..

2009-01-13T16:54:00.000-08:00

Java Platform, Micro Edition and Standards

1. What is the Java Platform, Micro Edition (Java ME)?

The Java Platform, Micro Edition (Java ME) is the Java platform targeted at consumer electronics and embedded devices like wireless phones, pagers, personal digital assistants, camcorders, game devices, small retail payment terminals and smart cards.

2. What are the principal components of Java ME platform technology?

Java ME platform technology has three components which, taken together, form a compliant Java application environment:

* A Configuration is a combination of a Java virtual machine and a set of application support APIs that are shared across a class of devices.

* A Profile is a set of APIs (designed for a specific configuration) that address the needs of a narrower device category.

* An Optional Package is a set of technology-specific APIs that extends the capabilities of a Java application environment.

A Java ME-compliant Java application environment requires both a configuration and a profile. Optional Packages provide device designers and other JCP participants with a standards-based extension framework.

3. How are Java ME standards defined?

Java technology standards are developed through the Java Community Process (JCP) by expert groups drawn from several industries. In this way, industry participants help shape Java ME standards targeted for their markets. For more information on the Java Community Process, see http://java.sun.com/aboutJava/communityprocess/. Java ME technology is built around JSRs, reference implementations and technology compatibility kits.

4. What is a JSR?

Java technology standards are delivered as Java Specification Requests (JSRs). Expert groups propose, develop and ratify JSRs through the Java Community Process.

5. What is a reference implementation?

A reference implementation (RI) is a working demonstration of a JSR. RIs are developed and licensed by the JSR specification lead.

6. What is a technology compatibility kit?

A technology compatibility kit (TCK) is a test suite that verifies whether an implementation is compliant with a given JSR. TCKs are developed and licensed by the JSR specification lead.

Sales and Licensing

1. What is the licensing model for Java ME technology?

The CDC reference implementation source code is available free of charge for education and research purposes under the Sun Community Source License Agreement (SCSL). If you plan to ship a commercial product that leverages Sun's source code, or if you want to use one of the CDC technology compatibility kits developed by Sun, you must sign a commercial license agreement with Sun.

2. Does Sun license only reference implementations and TCKs?

Sun also licenses optimized implementations of various JSRs, as well as different optimized versions of CDC HotSpot Implementation.

3. How can I contact a Sun OEM software sales representative?

Sales and licensing information is available from Sun sales representatives. For more information, contact Sun Microsystems Software and Technology.

CDC Products

1. What is CDC?

The Connected Device Configuration is a standards-based framework for building and delivering mobile applications that can be shared across a range of network-connected personal mobile devices. Typically, these devices include a 32-bit microprocessor/controller and require about 2 MB of RAM and 2.5 MB of ROM for the Java application environment.

2. What is CDC HotSpot Implementation?

The Connected Device Configuration HotSpot Implementation (formerly CVM) is a Java virtual machine that is highly optimized for resource-constrained devices like consumer products and embedded devices. CDC HotSpot Implementation combines full Java 2 compatibility with excellent performance, reliability and a low memory footprint.

3. How many Java virtual machine implementations does Sun have?

As the leader in Java virtual machine technology, Sun has developed several Java virtual machine implementations for different product scenarios and continues to perform research and development in this area. The following Java virtual machine technology products share the HotSpot brand:

* Java HotSpot Server is designed for multi-processor enterprise server environments that require maximum program execution speed, 64-bit support and very large memory heaps.

* Java HotSpot Client is designed for single-processor desktop environments that require faster start-up time and a smaller memory footprint.

* CDC HotSpot Implementation (formerly CVM) is designed for resource-constrained devices like consumer products and embedded devices. Typically, these devices include a 32-bit microprocessor/controller and require about 2 MB of RAM and 2.5 MB of ROM for the Java application environment. CDC HotSpot Implementation has excellent performance and reliability for low-memory conditions. Its portability interfaces make it rapidly adaptable for the many different kinds of platforms in the consumer and embedded market.

* CLDC HotSpot Implementation (formerly Monty) is designed for very small memory scenarios, typically 128 KB to 512 KB for the Java application environment. CLDC HotSpot Implementation also includes a portability interface for supporting alternate CPUs and operating systems.

4. For what platforms are implementations available?

Sun has developed optimized versions of CDC and CDC HotSpot Implementation for the ARM, PowerPC, MIPS and SPARC CPU architectures and the Linux and Solaris operating systems. The Personal Basis Profile reference implementation includes a device-driver based portability interface that includes a sample port based on X11. The Personal Profile reference implementation includes a sample port based on the GTK+ 1.2 toolkit. Other ports of Personal Profile include the QT application framework.

5. What profiles are currently available for CDC?

CDC currently supports three profiles. Foundation Profile provides basic application support APIs without any additional support for GUIs. Personal Basis Profile includes all of the APIs contained in Foundation Profile and adds support for lightweight AWT GUI components and the xlet application model. Personal Profile includes all of the APIs contained in Personal Basis Profile and adds support for full AWT compatibility and the applet application model.

6. What optional packages are currently available for CDC?

CDC currently supports several optional packages, with more on the way. RMI Optional Package supports remote method invocation based on the Java ME java.rmi package. JDBC Optional Package provides a subset of the JDBC 3.0 API for accessing tabular data sources including spreadsheets, flat files and cross-DBMS connectivity to a wide range of SQL databases. Mobile Media Optional Package supports access to audio, video and other time-based multimedia services on resource-constrained devices and allows Java applications to access device-level multimedia services.

7. What is the difference between CDC and CLDC?

These two Java ME configurations are designed around different target device footprints. CLDC is designed for very small memory scenarios, typically 128 KB to 512 KB while CDC is designed for more moderate memory scenarios, typically 2 MB of RAM and 2.5 MB of ROM. As a result, the CLDC APIs are very compact and do not require Java SE compatibility. CDC is based on Java SE compatibility for both APIs and tools.

8. What is the migration path for the PersonalJava, EmbeddedJava and JavaOS technologies?

These technologies precede both Java SE and the JCP standards organization. Rather than retrofit them into the JCP process they are being replaced by new JCP standards. The migration path for these legacy technologies is with CDC and its profiles.

Developers

1. What are the differences between the CDC APIs and Java SE APIs?

Most of the core APIs are identical between CDC and J2SE 1.3.1. The main differences are in java.awt and the omission of javax.swing and other large packages like org.omg.*. See CDC API Comparison for a description of the relationship between the J2SE 1.3.1 APIs and the CDC APIs.

2. Can I migrate my code from Java SE to CDC?

Because CDC includes the core application support APIs from J2SE 1.3.1, migrating code from a Java SE application environment to a CDC application environment is straightforward.

3. What are the differences between the CDC APIs and CLDC APIs?

The CDC and CLDC APIs are very different. The CLDC APIs were designed around very small resource configurations and therefore do not require Java SE compatibility. The CDC APIs were designed around more moderate memory constraints and the need for Java SE compatibility for both APIs and tools.

4. Can I migrate my code from CLDC to CDC?

Yes. CDC is a superset of CLDC functionality.

5. Can I migrate my code from MIDP to CDC?

No. The MIDP GUI APIs are different. We are investigating a solution for this.

6. What are the graphical user-interface options for CDC?

The basic CDC profiles each offer different GUI options. Foundation Profile has no GUI support and can be used for "headless" device scenarios or for supporting a device with a proprietary GUI. Personal Basis Profile provides just enough AWT functionality to support lightweight components. Personal Profile supports full AWT and applet compatibility.

7. What is an xlet?

The xlet application programming model is very similar to the applet application programming model. Xlets are loaded into an xlet manager and controlled through a life cycle interface. This is similar to how an applet is loaded and run inside a browser. The main difference is that the xlet application programming model does not have implicit API requirements like java.applet which allows it to be used in a greater variety of product scenarios.

8. What is the security model for CDC?

CDC uses the same policy-based security model that Java SE provides. This gives an application fine-grained control over the access and use of its external interfaces.

9. Is CDC compatible with Java SE tools?

Yes. CDC supports Java SE-based compilers, debuggers and profilers.

Reference:http://java.sun.com/javame/technology/cdc/faqs.jsp

Magazine

2009-01-05T04:37:00.000-08:00

Want to download the Computer magazine?
Get it here..
http://www522.megaupload.com/files/db86be88ac477ffd3888dbdfdefd37e7/MAGPcWdOc08.rar

Java ME

2009-01-05T04:32:00.001-08:00

Want to download Java ME Emulator?
Get it here...

JavaMEEmulator

Java Tutorials

2009-01-05T04:29:00.000-08:00

New To Java?
Want to be a Java Expert?
Go through the following website to master Java.
Work out the code samples given here..
www.java2s.com

RealPlayer

2009-01-05T04:26:00.000-08:00

Want RealPlayer Gold?
Get it here...
http://download.softpedia.com/dl/24d7b3cf4af268c3b95abf73cef06bc5/495bfc04/100008186/software/multimedia/video/RealPlayer11GOLD.exe

CCleaner

2009-01-05T04:25:00.000-08:00

Want to clear cache and fix
Registry Problems.
Get the CCleaner from the following link
ccleaner

Want To Download Internet Download Manager 5.15?

2009-01-05T04:21:00.000-08:00

Internet Download Manager (IDM) is an easy to use tool to increase download speeds by up to 500 percent, resume and schedule downloads. According to the opinions of IDM users Internet Download Manager is a perfect accelerator program to download your favorite software, games, cd, dvd and mp3 music, movies, shareware and freeware programs much faster!

Internet Download Manager has wide customization capabilities, downloadable skins, visual XP styles, multilingual interface, and supports proxy servers, FTP, HTTP and HTTPS protocols, firewalls, file redirects, cookies, directories with authorization, ZIP preview, categories, MP3 audio and MPEG video content processing and a large number of server platforms. IDM integrates seamlessly into Microsoft Internet Explorer, Netscape, AOL, MSN Explorer, Opera, and Mozilla browsers to automatically handle your downloads. You can also drag and drop files or use Internet Download Manager from command line. Internet Download Manager can dial your modem at the set time, download the files you want, then hang up or even shut down your computer when it's done.

Get this from the following Link
IDM 5.15

Want to Download Latest Firefox 3 .0.5?

2009-01-05T04:20:00.001-08:00

Click this link to download
Mozilla FireFox 3.0.5
Mozilla Firefox 3.0.5

Want To Download NetBeans 6.5 with JavaFX?

2009-01-05T04:15:00.000-08:00

Click this link to download for
Windows XP

NetBeans 6.5 With JavaFX

wireless Programming with JavA

2009-01-03T18:50:00.000-08:00

http://ifile.it/vdgah9e/0672321351.rar

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Security Issues with the Applet

2009-01-03T04:25:00.001-08:00

Java applet is run inside a web browser. But an applet is restricted in some areas, until it has been deemed trustworthy by the end user. The security restriction is provided for protecting the user by malicious code, like copy important information from the hard disk or deleting the files. Generally, applets are loaded from the Internet and they are prevented from: the writing and reading the files on client side. Some security issues to applet are following :

* Applets are loaded over the internet and they are prevented to make open network connection to any computer, except for the host, which provided the .class file. Because the html page come from the host or the host specified codebase parameter in the applet tag, with codebase taking precedence.

* They are also prevented from starting other programs on the client. That means any applet, which you visited, cannot start any rogue process on you computer. In UNIX, applets cannot start any exec or fork processes. Applets are not allowed to invoke any program to list the contents of your file system that means it cant invoke System.exit() function to terminate you web browser. And they are not allowed to manipulate the threads outside the applets own thread group.

* Applets are loaded over the net. A web browser uses only one class loader that’s established at start up. Then the system class loader can not be overloaded, overridden, extended, replaced. Applet is not allowed to create the reference of their own class loader.

* They cant load the libraries or define the native method calls. But if it can define native method calls then that would give the applet direct access to underlying computer.

JSF Interview Questions - 1

2009-01-03T04:19:00.000-08:00

1)What is JavaServer Faces?
JavaServer Faces (JSF) is a user interface (UI) framework for Java web applications. It is designed to significantly ease the burden of writing and maintaining applications that run on a Java application server and render their UIs back to a target client. JSF provides ease-of-use in the following ways:
Makes it easy to construct a UI from a set of reusable UI components
Simplifies migration of application data to and from the UI
Helps manage UI state across server requests
Provides a simple model for wiring client-generated events to server-side application code
Allows custom UI components to be easily built and re-used

Most importantly, JSF establishes standards which are designed to be leveraged by tools to provide a developer experience which is accessible to a wide variety of developer types, ranging from corporate developers to systems programmers. A "corporate developer" is characterized as an individual who is proficient in writing procedural code and business logic, but is not necessarily skilled in object-oriented programming. A "systems programmer" understands object-oriented fundamentals, including abstraction and designing for re-use. A corporate developer typically relies on tools for development, while a system programmer may define his or her tool as a text editor for writing code. Therefore, JSF is designed to be tooled, but also exposes the framework and programming model as APIs so that it can be used outside of tools, as is sometimes required by systems programmers.
2)How to pass a parameter to the JSF application using the URL string?
if you have the following URL: http://your_server/your_app/product.jsf?id=777, you access the passing parameter id with the following lines of java code:
FacesContext fc = FacesContext.getCurrentInstance();
String id = (String) fc.getExternalContext().getRequestParameterMap().get("id");
From the page, you can access the same parameter using the predefined variable with name param. For example,

Note: You have to call the jsf page directly and using the servlet mapping.

3)How to add context path to URL for outputLink?
Current JSF implementation does not add the context path for outputLink if the defined path starts with '/'. To correct this problem use #{facesContext.externalContext.requestContextPath} prefix at the beginning of the outputLink value attribute. For example:

4)How to get current page URL from backing bean?
You can get a reference to the HTTP request object via FacesContext like this:
FacesContext fc = FacesContext.getCurrentInstance();
HttpServletRequest request = (HttpServletRequest) fc.getExternalContext().getRequest(); and then use the normal request methods to obtain path information. Alternatively,
context.getViewRoot().getViewId();
will return you the name of the current JSP (JSF view IDs are basically just JSP path names).

5)How to access web.xml init parameters from java code?
You can get it using externalContext getInitParameter method. For example, if you have:

connectionString

jdbc:oracle:thin:scott/tiger@cartman:1521:O901DB

You can access this connection string with:
FacesContext fc = FacesContext.getCurrentInstance();
String connection = fc.getExternalContext().getInitParameter("connectionString");

6)How to access web.xml init parameters from jsp page?
You can get it using initParam pre-defined JSF EL valiable.
For example, if you have:

productId

2004Q4

You can access this parameter with #{initParam['productId']} . For example:
Product Id:

7)How to terminate the session?
In order to terminate the session you can use session invalidate method.
This is an example how to terminate the session from the action method of a backing bean:
Public String logout() {
FacesContext fc = FacesContext.getCurrentInstance();
HttpSession session = (HttpSession) fc.getExternalContext().getSession(false);
session.invalidate();
return "login_page";
}
The following code snippet allows to terminate the session from the jsp page:
<% session.invalidate(); %>

8)How to implement "Please, Wait..." page?
The client-side solution might be very simple. You can wrap the jsp page (or part of it you want to hide) into the DIV, then you can add one more DIV that appears when user clicks the submit button. This DIV can contain the animated gif you speak about or any other content.
Scenario: when user clicks the button, the JavaScript function is called. This function hides the page and shows the "Wait" DIV. You can customize the look-n-fill with CSS if you like.

10)How to download PDF file with JSF?
This is an code example how it can be done with action listener of the backing bean.
Add the following method to the backing bean:
public void viewPdf(ActionEvent event) {
String filename = "filename.pdf";
// use your own method that reads file to the byte array
byte[] pdf = getTheContentOfTheFile(filename);
FacesContext faces = FacesContext.getCurrentInstance();
HttpServletResponse response = (HttpServletResponse) faces.getExternalContext().getResponse();
response.setContentType("application/pdf");
response.setContentLength(pdf.length);
response.setHeader( "Content-disposition", "inline; filename=\""+fileName+"\"");
try {
ServletOutputStream out;
out = response.getOutputStream();
out.write(pdf);
} catch (IOException e) {
e.printStackTrace();
}
faces.responseComplete();
}
This is a jsp file snippet:

JNI Interview Questions & Answers

2009-01-03T04:17:00.000-08:00

1)How to debug JNI code in CVM?
Porting Guide for the CDC and the Foundation Profile from SUN has a chapter on "C Debugging with GDB".

2)How can I check the status of a java Thread using JVMDI?
// ThreadTool.java class ThreadTool { public static final int THREAD_STATUS_UNKNOWN = -1; public static final int THREAD_STATUS_ZOMBIE = 0; ...

3)Is there a COM Bridge that lets Windows developers create native client applications that access Enterprise JavaBeansTM (EJBTM) components deployed on a J2EE App server?
Yes. Take a look at: JavaTM 2 Platform, Enterprise Edition Client Access Services (J2EETM CAS) COM Bridge 1.0 Early Access.

4)What is necessary to have an applet call a native method? DLL installation, code signing, specific security permissions needed.
After more tries I solved the problem. I used your posted response about such a thing for Netscape. But was difficult to use that answer because Netscape...

5)JDK 1.4 has introduced the concept of direct buffers. Where can I get more information and/or samples for manipulating direct buffers?
JNI has been enhanced in v 1.4 to reflect a new feature of the java.nio package: direct buffers. The contents of a direct buffer can, potentially, reside...

6)What are the basic techniques for debugging mixed java and C++ code?
Debugging integrated Java and C/C++ code illustrates the two basic approaches using JNI (call C/C++ code from java, embed jvm in C/C++ code) and ways to...
EJB-JNI-Legacy Integration (C++ API) we have existing System in C++.We want to use Existing in the intranet/internet. We are using JNI to use existing System. And then we are calling JNI Classes in...
EJBs are supposed to be portable between different app servers who comply with the Sun's specifications for compliant EJB containers. Because of this reason,

7)Anyone know of a way of marking a Java thread as being a demon if it was "created" through the JNI AttachCurrentThread call?
Through a new method called AttachCurrentThreadAsDaemon.

8)What is Signal Chaining mechanism that has been implemented in JDK 1.4?
Signal-chaining enables the Java Platform to better interoperate with native code that installs its own signal handlers. The facility works on both Solaris and Linux platforms.

The signal-chaining facility was introduced to remedy a problem with signal handling in previous versions of the Java Hotspot VM. Prior to version 1.4, the Java Hotspot VM would not allow application-installed signal handlers for certain signals including, for example, SIGBUS, SIGSEGV, SIGILL, etc, since those signal handlers could conflict with the signal handlers used internally by the Java Hotspot VM.
The signal-chaining facility offers:
A. Support for pre-installed signal handlers when the Hotspot VM is created.
B. Support for signal handler installation after the Hotspot VM is created, inside JNI code or from another native thread.

Pre-installed signal handlers (A) are supported by means of saving existing signal handlers, for signals that are used by the VM, when the VM is first created. Later, when any of these signals are raised and found not to be targeted at the Java Hotspot VM, the pre-installed handlers are invoked. In other words, pre-installed handlers are "chained" behind the VM handlers for these signals.

9)Is there a TCL-Java Bridge?
Yes, The Tcl/Java project currently has two packages, Jacl and Tcl Blend. Jacl, which stands for Java Command Language, is a Java implementation of Tcl..

PHP – Variables

2009-01-03T04:15:00.000-08:00

If you have never had any programming, Algebra, or scripting experience, then the concept of variables might be a new concept to you. A detailed explanation of variables is beyond the scope of this tutorial, but we've included a refresher crash course to guide you.

A variable is a means of storing a value, such as text string "Hello World!" or the integer value 4. A variable can then be reused throughout your code, instead of having to type out the actual value over and over again. In PHP you define a variable with the following form:

$variable_name = Value;

If you forget that dollar sign at the beginning, it will not work. This is a common mistake for new PHP programmers!

Note: Also, variable names are case-sensitive, so use the exact same capitalization when using a variable. The variables $a_number and $A_number are different variables in PHP's eyes.

A Quick Variable Example

Say that we wanted to store the values that we talked about in the above paragraph. How would we go about doing this? We would first want to make a variable name and then set that equal to the value we want. See our example below for the correct way to do this.

PHP Code:

Note for programmers: PHP does not require variables to be declared before being initialized.

PHP Variable Naming Conventions

There are a few rules that you need to follow when choosing a name for your PHP variables.

PHP variables must start with a letter or underscore "_".

PHP variables may only be comprised of alpha-numeric characters and underscores. a-z, A-Z, 0-9, or _ .

Variables with more than one word should be separated with underscores. $my_variable

Variables with more than one word can also be distinguished with capitalization. $myVariable

PHP – Echo

As you saw in the previous lesson, the PHP command echo is a means of outputting text to the web browser. Throughout your PHP career you will be using the echo command more than any other. So let's give it a solid perusal!

Outputting a String

To output a string, like we have done in previous lessons, use PHP echo. You can place either a string variable or you can use quotes, like we do below, to create a string that the echo function will output.

PHP Code:

I love using PHP!";

?>

Display:

Hello!

I love using PHP!

In the above example we output "Hello!" without a hitch. The text we are outputting is being sent to the user in the form of a web page, so it is important that we use proper HTML syntax!

In our second echo statement we use echo to write a valid Header 5 HTML statement. To do this we simply put the

at the beginning of the string and closed it at the end of the string. Just because you're using PHP to make web pages does not mean you can forget about HTML syntax!

Careful When Echoing Quotes!

It is pretty cool that you can output HTML with PHP. However, you must be careful when using HTML code or any other string that includes quotes! Echo uses quotes to define the beginning and end of the string, so you must use one of the following tactics if your string contains quotations:

Don't use quotes inside your string

Escape your quotes that are within the string with a backslash. To escape a quote just place a backslash directly before the quotation mark, i.e. \"

Use single quotes (apostrophes) for quotes inside your string.

See our example below for the right and wrong use of echo:

PHP Code:

I love using PHP!

";

// OK because we escaped the quotes!

echo "

I love using PHP!

";

// OK because we used an apostrophe '

echo "

I love using PHP!

";

?>

If you want to output a string that includes quotations, either use an apostrophe ( ' ) or escape the quotations by placing a backslash in front of it ( \" ). The backslash will tell PHP that you want the quotation to be used within the string and NOT to be used to end echo's string.

Echoing Variables

Echoing variables is very easy. The PHP developers put in some extra work to make the common task of echoing all variables nearly foolproof! No quotations are required, even if the variable does not hold a string. Below is the correct format for echoing a variable.

PHP Code:

Display:

Hello Bob. My name is: 4a

Echoing Variables and Text Strings

You can also place variables inside of double-quoted strings (e.g. "string here and a $variable"). By putting a variable inside the quotes (" ") you are telling PHP that you want it to grab the string value of that variable and use it in the string. The example below shows an example of this cool feature.

PHP Code:

";

echo "Hi, I'm Bob. Who are you? $my_string
";

echo "Hi, I'm Bob. Who are you? $my_string Bobetta";

?>

Display:

Hello Bob. My name is: Bobetta

Hi, I'm Bob. Who are you? Hello Bob. My name is:

Hi, I'm Bob. Who are you? Hello Bob. My name is: Bobetta

By placing variables inside a string you can save yourself some time and make your code easier to read, though it does take some getting used to. Remember to use double-quotes, single-quotes will not grab the value of the string. Single-quotes will just output the variable name to the string, like )$my_string), rather than (Hello Bob. My name is: ).

PHP Echo - Not a Function

Echo is not a function, rather it is a language construct. When you use functions in PHP, they have a very particular form, which we will be going over later. For now, just know that echo is a special tool that you'll come to know and love!

Java Reporting Made Easy

2009-01-03T04:14:00.000-08:00

Overview

ReportMill is the best Java application reporting tool available for dynamically generating reports and web pages from Java applications in formats such as PDF, HTML, Flash, Excel and more. ReportMill combines an easy-to-use page layout application and a powerful Java API in a single compact jar file, which is remarkably easy to integrate into your custom Java application.

Embedded Reporting

Running as Java code inside your application, ReportMill seamlessly harvests data directly from any Java dataset, whether EJBs, POJOs (Plain Old Java Objects), Java Collection classes, JDBC ResultSets or any combination of these. This is much more efficient than traditional reporting tools, which often require developers to repackage existing Java datasets as the original SQL query, then force a redundant refetch and some potentially risky inter-process communication.

This architecture also provides unique access to custom business logic found in the developer's object model, providing a significant savings by reusing this code instead of forcing a rewrite in proprietary template macro languages.

Powerful Design Application
ReportMill is the only reporting tool built on top of a comprehensive page layout application . This ensures that almost any page or report design can be accommodated and also makes template design more intuitive for anyone who has made a newsletter or "For Sale" sign in any of the popular page layout applications.

Downlaod The ReportMill

http://reportmill.com/product/

Simple API

Most developers need to call only three lines of ReportMill API. Since ReportMill harvests data from any Java dataset using reflection and common collections interfaces, there is no need to write any binding/feeder code, implement any interfaces or create any datasource objects.

Online Aptitude Tests

2009-01-03T04:12:00.000-08:00

1) Which of the following countries has launched the solar observation satellite solar-B ?

1) Japan

2) China

3) Russia

4) USA

2) A Great way to fly is the media campaign of which of the following airlines?

1) Lufthansa

2) Fly Emirates

3) Jet Airways

4) Singapore Airlines

3) Who among the following is the author as the book mein kampf?

1) Rudyard Kipling

2) Adolf Hitler

3) Arnold Toynbee

4) Charles Dickens

4) Who among the following were the founders of the Vijayanagar empire?

1) Krishna Deva Raja

2) Saluva Narsimha

3) Deva Raja II

4) Harihara and Bukka

5) What is the correct expansion of the abbreviation NASA?

1) National Aeronautical Science Association

2) New Aeronautical and Science Agency

3) National Aeronautics and space Administration

4) None of these

6) At which of the following places on the globe has the highest temperature been recorded?

1) Al Azizyah

2) Jacobabad

3) Cairo

4) None of these

7) The Indio constitution is divided into how many parts?

1) Twenty-Two

2) Twenty

3) Eighteen

4) Sixteen

8) The first five year plan of India started in

1) 1952-53

2) 1951-52

3) 1956-57

4) 1948-49

9) The first Indian woman president of the Indian National Congress was

1) Sarojini Naidu

2) Nellie Sengupta

3) Annie Besant

4) Aruna Asaf Ali

10) The first bowler to take all the 10 wickets in a test innings was

1) Anil Kumble

2) Richard Hadlee

3) Jim Laker

4) Shane Warne

11) The first Indian tennis player to win a Grand Slam event

1) Ramanathan Krishanan

2) Mahesh Bhupati

3) Ramesh Krishanan

4) Leander paes

12) The first train in India from Bombay to Thane ran in

1) 1857

2) 1855

3) 1860

4) 1853

13) How many PIN code zone are there in India?

1) 7

2) 9

3) 8

4) 6

14) The film DON is a remake of an old film of the same name. Who is the director of the present DON?

1) Shahrukh Khan

2) Rakesh Mehra

3) Ram Gopal Verma

4) Farhan Akhtar

15) The new Chief Minister of the Jharkhand is

1) Arjun Munda

2) Madhu Koda

3) Shibu Soren

4) None of these

Ans:
1) 1 2) 4 3) 2 4) 4 5) 3
6) 1 7) 1 8) 2 9) 1 10) 3

11) 1 12) 4 13) 3 14) 4 15) 2

Hibernate Interview Questions

2009-01-03T04:11:00.000-08:00

1.What is Hibernate?
Hibernate is a powerful, high performance object/relational persistence and query service. This lets the users to develop persistent classes following object-oriented principles such as association, inheritance, polymorphism, composition, and collections.

2.What is ORM?
ORM stands for Object/Relational mapping. It is the programmed and translucent perseverance of objects in a Java application in to the tables of a relational database using the metadata that describes the mapping between the objects and the database. It works by transforming the data from one representation to another.

3.What does an ORM solution comprises of?
It should have an API for performing basic CRUD (Create, Read, Update, Delete) operations on objects of persistent classes
Should have a language or an API for specifying queries that refer to the classes and the properties of classes
An ability for specifying mapping metadata
It should have a technique for ORM implementation to interact with transactional objects to perform dirty checking, lazy association fetching, and other optimization functions

4.What are the different levels of ORM quality?

There are four levels defined for ORM quality.

Pure relational

Light object mapping

Medium object mapping

Full object mapping

5.What is a pure relational ORM?
The entire application, including the user interface, is designed around the relational model and SQL-based relational operations.

6.What is a meant by light object mapping?
The entities are represented as classes that are mapped manually to the relational tables. The code is hidden from the business logic using specific design patterns. This approach is successful for applications with a less number of entities, or applications with common, metadata-driven data models. This approach is most known to all.

7.What is a meant by medium object mapping?
The application is designed around an object model. The SQL code is generated at build time. And the associations between objects are supported by the persistence mechanism, and queries are specified using an object-oriented expression language. This is best suited for medium-sized applications with some complex transactions. Used when the mapping exceeds 25 different database products at a time.

8.What is meant by full object mapping?
Full object mapping supports sophisticated object modeling: composition, inheritance, polymorphism and persistence. The persistence layer implements transparent persistence; persistent classes do not inherit any special base class or have to implement a special interface. Efficient fetching strategies and caching strategies are implemented transparently to the application.

9.What are the benefits of ORM and Hibernate?
There are many benefits from these. Out of which the following are the most important one.
Productivity – Hibernate reduces the burden of developer by providing much of the functionality and let the developer to concentrate on business logic.

Maintainability – As hibernate provides most of the functionality, the LOC for the application will be reduced and it is easy to maintain. By automated object/relational persistence it even reduces the LOC.

Performance – Hand-coded persistence provided greater performance than automated one. But this is not true all the times. But in hibernate, it provides more optimization that works all the time there by increasing the performance. If it is automated persistence then it still increases the performance.

Vendor independence – Irrespective of the different types of databases that are there, hibernate provides a much easier way to develop a cross platform application.

10.How does hibernate code looks like?

Session session = getSessionFactory().openSession();
Transaction tx = session.beginTransaction();
MyPersistanceClass mpc = new MyPersistanceClass ("Sample App");
session.save(mpc);
tx.commit();
session.close();

The Session and Transaction are the interfaces provided by hibernate. There are many other interfaces besides this.

JMS Questions & Answers

2009-01-03T04:10:00.000-08:00

1.What are the advantages of JMS?

JMS is asynchronous in nature. Thus not all the pieces need to be up all the time for the application to function as a whole. Even if the receiver is down the MOM will store the messages on it's behalf and will send them once it comes back up.

2.What is the difference between topic and queue?

A topic is typically used for one to many messaging i.e. it supports publish subscribe model of messaging. While queue is used for one-to-one messaging i.e. it supports Point-to-Point Messaging.

3.What is the use of Message object?

Message is a lightweight message having only header and properties and no payload.

4.What are the two different types of messaging models that are supported by JMS?

1. Point-to-Point
2. Publish and Subscribe.

5.What information is stored in the Header of a ‘Message’?

Message identification and routing information.

6.What are the types of acknowledgments?

1) Acknowledgment by commits. – Acknowledgement happens automatically when a transaction is committed.

2) Session.AUTO_ACKNOWLEDGE

3) Session.CLIENT_ACKNOWLEDGE – client must call the acknowledge( ) method

4) Session.DUPS_OK_ACKNOWLEDGE –Session acknowledges the message after it has been delivered. This may result in the delivery of some duplicate messages if the JMS provider fails.

7.What happens to messages if a transaction is rolled back?

All consumed messages are re-delivered.

8.What is text message?

Text messages contain String messages. It is useful for exchanging textual data and complex character data like XML.

9.What is the Role of the JMS Provider?

The JMS provider handles security of the messages, data conversion and the client triggering. The JMS provider specifies the level of encryption and the security level of the message, the best data type for the non-JMS client.

10.What are the advantages of JMS?

One of the principal advantages of JMS messaging is that it's asynchronous. Thus not all the pieces need to be up all the time for the application to function as a whole.

Excellent J2ME E books Links

2008-12-31T20:09:00.000-08:00

Disclaimer:
The links shown here are obtained from internet.
The content provided in this website are hosted in the external server and we are not responsible for any broken links or materials.

proj2mepolish

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Java complete reference
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SAMS J2ME in 21 days

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Core J2ME

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wireless J2ME Programming
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J2ME Gaming

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Networking Questions

2008-12-31T14:11:00.002-08:00

1. What is the difference between URL instance and URLConnection instance?

A URL instance represents the location of a resource, and a URLConnection instance represents a link for accessing or communicating with the resource at the location.
2. How do I make a connection to URL?

You obtain a URL instance and then invoke openConnection on it. URLConnection is an abstract class, which means you can't directly create instances of it using a constructor. We have to invoke openConnection method on a URL instance, to get the right kind of connection for your URL. Eg. URL url;

URLConnection connection;
try{ url = new URL("...");
connection = url.openConnection();
}catch (MalFormedURLException e) { }

3. What Is a Socket?

A socket is one end-point of a two-way communication link between two programs running on the network. A socket is bound to a port number so that the TCP layer can identify the application that data is destined to be sent. Socket classes are used to represent the connection between a client program and a server program. The java.net package provides two classes--Socket and ServerSocket--which implement the client side of the connection and the server side of the connection, respectively.
4. What information is needed to create a TCP Socket?

The Local System?s IP Address and Port Number. And the Remote System's IPAddress and Port Number.
5. What are the two important TCP Socket classes?

Socket and ServerSocket. ServerSocket is used for normal two-way socket communication. Socket class allows us to read and write through the sockets. getInputStream() and getOutputStream() are the two methods available in Socket class.
6. When MalformedURLException and UnknownHostException throws?

When the specified URL is not connected then the URL throw MalformedURLException and If InetAddress? methods getByName and getLocalHost are unable to resolve the host name they throw an UnknownHostException.
7. What does RMI stand for?

It stands for Remote Method Invocation.

8. What is RMI?

RMI is a set of APIs that allows to build distributed applications. RMI uses interfaces to define remote objects to turn local method invocations into remote method invocations.

Data Structure- Frequently Asked Questions

2008-12-31T14:11:00.001-08:00

1.) What is Heap data structure?

The binary heap data structures is an array that can be viewed as a complete binary tree. Each node of the binary tree corresponds to an element of the array. The array is completely filled on all levels except possibly lowest.

2.) What are the major data structures used in the following areas : RDBMS, Network data model & Hierarchical data model?

1. RDBMS Array (i.e. Array of structures)
2. Network data model Graph
3. Hierarchical data model Trees.

3.) Why is the isEmpty() member method called?

The isEmpty() member method is called within the dequeue process to determine if there is an item in the queue to be removed i.e. isEmpty() is called to decide whether the queue has at least one element. This method is called by the dequeue() method before returning the front element.

4.) What method is used to place a value onto the top of a stack?

push() method, Push is the direction that data is being added to the stack. push() member method places a value onto the top of a stack.

5.) What is Linked List ?

Linked List is one of the fundamental data structures. It consists of a sequence of? nodes, each containing arbitrary data fields and one or two (”links”) pointing to the next and/or previous nodes. A linked list is a self-referential datatype because it contains a pointer or link to another data of the same type. Linked lists permit insertion and removal of nodes at any point in the list in constant time, but do not allow random access.

6.) Difference between calloc and malloc?

malloc: allocate n bytes calloc: allocate m times n bytes initialized to 0

7.) How many parts are there in a declaration statement?

There are two main parts, variable identifier and data type and the third type is optional which is type qualifier like signed/unsigned.

8.) What is the difference bitween NULL AND VOID pointer?

NULL can be value for pointer type variables. VOID is a type identifier which has not size. NULL and void are not same.
Example: void* ptr = NULL;

HOW TO SURVIVE A HEART ATTACK WHEN ALONE

2008-12-31T14:09:00.000-08:00

Since many people are alone when they suffer a heart

attack, without help,the person whose heart is beating

improperly and who begins to feel faint, has only

about 10 seconds left before losing consciousness.

However,these victims can help themselves by coughing

repeatedly and very vigorously. A deep breath should

be taken before each cough, and the cough must be deep

and prolonged, as when producing sputum from deep

inside the chest.

A breath and a cough must be repeated about every two

seconds without let-up until help arrives, or until

the heart is felt to be beating normally again.

Deep breaths get oxygen into the lungs and coughing

movements squeeze the heart and keep the blood

circulating. The squeezing pressure on the heart also

helps it regain normal rhythm. In this way, heart

attack victims can get to a hospital. Tell as many

other people as possible about this. It could save

their lives!!

A cardiologist says If everyone who gets this mail

sends it to 10 people, you can bet that we'll save at

least one life.

BE A FRIEND AND PLEASE SEND

THIS ARTICLE TO AS MANY FRIENDS ! AS POSSIBLE ..

Thanks and Regards,

Want to Download NetBeans IDE 6.0?

2008-12-31T14:03:00.001-08:00

http://download.netbeans.org/netbeans/6.0/final/?cid=921887

Ask Yourself These Questions

2008-12-31T13:59:00.000-08:00

What jobs suit me?
Ask yourself what is really important to you and what you are willing to do. Everyone has unique motivations and ambitions. Yours may be different from people you know. Writing your ideas down or having conversations may help you capture your thoughts.

Help making decisions
Try what jobs would suit me?, a tool designed to assist you with the decision-making process. After answering a series of questions, see, which jobs might best, match your preferences. Compare two jobs side-by-side or start by considering an employment sector. Your friends and family may help you identify the key deciding factors for your career planning and may point out strengths that you take for granted. Your university careers service has a wealth of resources to support career research and planning. As well as talking to a careers adviser, you may gain insights from psychometric tests, which focus on aptitude, ability, or personality. Ask which psychometric tests are available or have a look at psychometric tests.

What do different jobs entail?
Learning what people actually do on a day-to-day basis is a crucial step in your job search. Understanding jobs is the best way to ensure you make the right decision for you. It is also essential for writing strong applications, which persuade a company or organization that you are a good fit for the job. Get more details about jobs you are considering at explore types of jobs. Be sure to read the case studies. Alternatively, you may start your job search by looking at all the related jobs in a sector at explore job sectors.

How do I use my degree?
You may want to directly apply your subject-related knowledge and skills to the world of work. Ask your university careers service for the results of previous surveys, which may provide some insight into what people with your degree have gone on to do. Visit what do graduates do? to view national survey results of what students on your course have pursued. Also, find out about options with your degree by looking at options with your subject.

These 10 tips will make sure that your job chances stay on the right track.

You have decided to look for a new job. But, in the haste to land your new job, you need to make sure that you have covered all the bases and approach your job search in a patient and professional manner.

1. Develop a job search plan
The old adage "fail to plan, plan to fail" is as true now as it has ever been. If you know where you want to be and the job you want, it is easier to get there. Therefore, split your job search into short- and long-term goals and identify the actions you need to take in order to reach them.

The more you know about your goals and the more ways you search for your next job, the greater your chances of finding your ideal job.

2. List your achievements
Employers want to know if you have the skills and experience they are looking for because they need to determine "What can this person do for my business?" They want to see evidence of jobs you have done that went above and beyond the basic requirements of your job role.

Look back over the last 12 months and pick out any notable successes or special projects that you were involved in -- this can then be used to show an employer when you are at interview stage. After all, if you have a trumpet to blow then blow it.

3. Revamp your CV
Your CV is designed to do just one thing: to get you an interview. The average recruiter will only spend between 20 to 30 seconds glancing at a CV which means that you need to make an impression quickly and sell yourself.

Writing a winning CV can be a challenge. But, by putting the mileage, in you will have a document that will make potential employers take action and invite you for an interview.

4. Decide the type of company you want to work forYou spend almost 70 per cent of your time at work during the course of a year, so it is important that you work in an environment and culture that you can enjoy and thrive. And, that means targeting organizations that match your goals and career values.

After all, you don't want to find yourself embarking on the same exercise again this time next year because you made a decision in haste.

5. Use the Web
OK, so you are already on the Web but are you really using it to your advantage as a tool to help you get your next job? No? Then post your CV online, create your own personal account on different job boards and keep up to date with developments in your chosen field by reading the online community pages which will also give information about working in different sectors within your industry. Knowledge is power, they say.

6. Network
Talk to friends, call old work colleagues and attend industry trade shows or networking events. Networking may sound daunting but the more events you attend the easier it becomes. And, the higher up the corporate ladder you move the more and more everybody knows everybody else and a referral from one of your contact could help your career.

7. Customise your CV and covering letter
It may seem tempting to simply cut and paste the same CV and covering letter to several employers, but it could cost you in the long run. Tailor your CV to the job you are applying and only include relevant information that will demonstrate how your experience links to the advertised position.

For instance, if you are applying for a marketing role, make sure that your CV has a marketing bias highlighting your experience in this field.

8. Dress to impress
Shakespeare once said: "Apparel oft proclaims the man." Your image is the outer reflection of your inner self allowing people to judge and make assumptions of your personality and attitudes. Dressing successfully (or unsuccessfully) can make or break your interview. Dress for the job you want not the job you already have.

9. Stay positive and avoid neg-heads
Job seeking is never easy and there will be times when you will want to give up and resign yourself to staying in your current job. But don't give up.

Experts estimate that the average job search can last anywhere from two to 10 months. So be patient and have the belief that you will find your dream job just around the corner. As Henry Ford said: "If you think you can or you think you can't, you're probably right."

10. Be good to yourself
Searching for a job is a job in itself and, unless you take a break away from it, you could start to feel exhausted and burnt out. Don't allow it to consume your every waking moment. Allow time to relax with friends, listen to your iPod or go to the gym and participate in activities that you enjoy. Clearing your mind and replenishing your energy will enable you to resume your job search feeling refreshed and rejuvenated.

Six Common Interview Mistakes

2008-12-31T13:58:00.000-08:00

AVOID SIX COMMON INTERVIEW MISTAKES

Tip # 1: Don't discuss pay too early
As the manager of a software store for 10 years, I can honestly say that questions about pay in the first interview from anyone other than a temporary applicant always bothered me a little. Temp jobs aside, if you are not really out there just for the money, asking this question right out of the gate is going to make any other questions you ask sound conniving and insincere. Unless the subject comes up, don't wade into the issue of the pay in the first interview. You can talk about it after you impress the employer enough for a second interview.

Tip # 2: Talk tech to techies only
Feel free to discuss what you know, but remember: If you are talking to a nontechnical manager or human resources representative, you are not going to impress them with talk about life in the trenches. My previous supervisor was totally unimpressed with anything to do with technology. A sure way to put the man to sleep was to begin any story that had to do with computers.
When I interviewed for a previous position, the department manager actually had a technically savvy person participate in the interview to ask and respond to questions she would not understand. When I saw this tactic being used, I knew it was not a time to try to impress with a lot of techno babble.
Answer questions about your work history briefly and keep the tech comments to a minimum until you know the history of the company and the people involved in the hiring process. If you have questions about the technology in use at the site, keep your questions specific and relevant to the position for which you are applying.

Tip # 3: Keep your philosophy to yourself
If you hate Bill Gates, Windows XP, and the whole Office Suite, keep it to yourself. Ranting about your tech philosophy can ruin your chances at the position.
I once interviewed a young man for a retail sales position in a software store. When I asked about his opinion of the then-new Windows 98, the applicant ranted about "the revolution of UNIX" and loosening the grip of Microsoft on the PC market. I am not exaggerating; the man sounded like he was ready to sign on to a paramilitary group. I almost didn't have the heart to tell him my company was a Value Added Reseller for Microsoft.
Chances are, you will work with many people who need your help with one of the Microsoft products, so you don't want to blast the tools you will likely be using and supporting. If you are asked about how you feel about a product, be honest, but don't preach. The interviewer probably just wants to see how you respond to such questions.

Tip # 4: Don't climb the advancement ladder in the interview
If you are joining the ranks of a new company, the last thing the interviewer wants to hear is, "How fast can I get out of this job?" Do not ask about opportunities for advancement until the second or third interview. If you are joining a company just to advance into another position, silence is golden. Keep it to yourself unless the interviewer asks or unless it is somehow already known that you'll be advancing quickly. Remember that what you say now can come back to haunt you later. You don't want to brag to someone who might be under your wing after a promotion.
Further, you never know what may happen if you actually get the job. Learn to accept and adapt and, above all, be happy you have a job.
Due to downsizing, a former coworker of mine did not move into the network administration position she wanted and was expecting to get. The bitterness fostered by her broken expectations eventually caused her to resign. In the tight job market of the time-similar to the one now-and with her lack of certified qualifications, she ended up seeking work at a local restaurant.

Tip # 5: Avoid the dreaded electronic interruption
Cellular phone and pager etiquette might seem a trivial thing to those that are hooked up, but you can kiss any job opportunity goodbye if you interrupt an interview to take a telephone call, especially if the human resources representative has a low tolerance for personal digital devices. Only if you are exchanging information by invitation should you reveal the fact that you carry a PDA. If you wear it on a belt loop or somewhere that is exposed, lose it, along with any other electrical device hooks and loops, and store them in pocket, purse, or briefcase. If you can't spare the time away from the rest of the world to do an interview, why are you applying for the job?
I have conducted training classes with people who, when asked to turn off their phones and pagers during class, place their devices in silent mode. When giving a lecture to a class or holding a discussion, watching a person being silently buzzed is terribly distracting and also aggravating.
If you think getting rid of electronic communications devices isn't important, just ask any human resources rep who has had a person answer a cellular phone during a job interview. Then ask if the person got the job.

Tip # 6: Remember to say thank you
Beyond thanking your interviewers for their time as you leave, it's vital that you follow up in written form. If the competition for a position is tight, a follow-up thank you note can mean a lot. If the manager is slow to hire, the arrival of a thank-you note can serve as a reminder about the candidate who's awaiting the manager's next move.
Just after you've completed the interview, take note of anything specific you discussed and make a point of referencing it in your thank you letter. Even a nice greeting card is better than nothing.
It may seem like a small detail, but the experts will tell you that this tried-and-true tactic really makes an impact. A coworker of mine, who successfully worked as a job coach, used to keep a stack of generic notes in her desk. When a participant in her program applied for a job somewhere, she would give the person one of these notes to have them drop in the mail on the way home.

How to improve your Presentation Skills?

2008-12-31T13:56:00.000-08:00

According to experts in the field of communication training, presentation skills includes not only, aspects relating to non-verbal skills, etiquette and grooming, but also other factors such as listening and speaking.

In order to ensure effective communication and presentation skills one needs to keep the following factors in mind:

In order to ensure effective communication and presentation skills one needs to keep the following factors in mind:

Avoid ambiguity
Accept feedback in order to gain confirmation and rule out confusion

The non-verbal presentation factors are:

Voice: This implies the tone – sarcastic or sincere; warm or cold; rich and expressive; or dull and flat. The other voice aspect is the volume – shouting, barely audible or medium volume.

Speech pattern: slow, hesitant, fast, jerky, abrupt or even-steady pace.

Facial expression: This includes:
The brow/forehead: Wrinkled or smooth
Eyebrows: wrinkled or smooth
Jaw/mouth region: firm or relaxed

Eye contact: Whether the speaker is looking at the listener/audience being addressed.

Gestures: This includes the hand movements such as: hand-wringing, open hand movements, finger pointing, fist thumping, etc.

Postures: This is important, as it shows how interested the speaker or listener is.

Body movement: This includes the movement of the body such as shrugs and shuffles, arms crossed or left lose, strides or standing in one position.

Tips to Improve Your Conversational Skills

1.Choose an article or short story to read with a friend or classmate. Discuss the article together.

2.Choose an article or short story to read with a friend or classmate. Each person should write down five questions about the article and his / her partner.

3.Read a few articles to develop a debate. Hold the debate in class making arguments based on what you have read.

4.Read a short play with a few friends. Continue the conversation by each taking a character from the play and having a discussion about something that happened in the play.

5.Read dialogues. Once you've practiced the written texts, improvise a continued conversation using the same characters as in the dialogue.

6.Read short biographies. Pair up with a friend or classmate and take on the roles of interviewer and famous person.

Java and OOPS

2008-12-31T13:52:00.000-08:00

1.) Why JAVA is known as securable language?

There are two reasons behind this. The first one is, as JAVA runs in JVM, which is a virtual machine, and it converts source code to byte code, which is not understandable for humans, so its safe. The second reason is JAVA does not support the Pointer concept, hence we can say that JAVA is a securable language.

2.) What is the necessity of Interface?

As java is a Partially Object Oriented language, and it does not support the multiple inheritance concepts, it creates problem for the developers. To over come this situation JAVA provides Interface concept for multiple inheritance.

3.) What is Abstraction?

An essential element of object-oriented programming is abstraction. Abstraction is the process to hide the complexity. A powerful way to manage abstraction is through the use of hierarchical classifications. This allows programmer to understand the semantics of complex system.

4.) What is Polymorphism?

The meaning of Polymorphism is something like one name many forms. Polymorphism enables one entity to be used as general category for different types of actions. The specific action is determined by the exact nature of the situation. The concept of polymorphism can be explained as “one interface, multiple methods”.

5.) What is Inheritance?

Inheritance is the process of basing one class on another. In this process, a base class provides methods, properties, and other members to a derived class. The advantage of inheritance is that you can write and maintain code once it is in the base class and reuse it over and over in the derived classes. But the main draw back of Java is it doesn’t support multiple Inheritances; hence to over come this draw back Java provides us the Interface concept.

6.) What is Object Oriented Programming Language ?

The language, which obeys all the basic principles of Object Oriented Programming, which are Encapsulation, Inheritance and Polymorphism, is generally known as Object Oriented Programming Language. Languages like c++ and java are some well-known Object Oriented Programming Languages.

7.) What is Encapsulation?

Encapsulation is a process of binding or wrapping the data and the codes that operates on the data into a single entity. This keeps the data safe from outside interface and misuse.

8.) What is Class and Object?

A class defines the abstract characteristics of a thing (object), including the thing’s characteristics, like its attributes or properties and the things it can do .The code for a class should be relatively self-contained. Collectively, the properties and methods defined by a class are called members. Object a particular instance of a class. Object holds the characteristics of the Class. The set of values of the attributes of a particular object is called its state.

9.) Is JAVA a completely Object Oriented Programming Language?

The answer to this question is certainly no. The reason behind this is JAVA does not obey the OOPs concept purely. Certain concepts like Operator over loading and Multiple Inheritance are not supported by JAVA. Hence JAVA is known as Partially Object Oriented Programming Language.

10 Costly Mistakes at Your Communication

2008-12-31T13:51:00.000-08:00

Communication in simple terms means transfer of information. Communication becomes a successful process only when the information transferred is received by the receiver in the same sense.

Communication has its own importance in all aspects of life. Communication becomes easy only when the information is shared in simple and plain terms. Many of us make several mistakes in communication. Such mistakes are always unnoticed by us and we never try to rectify those.

Here are the 10 common communication mistakes listed out.

1. Talking fast and rapidly:
This is the most common mistake a person makes while communicating with others. A clear conversation is more clearly understandable. While talking too fast makes the listener impatience and confused.

2. Talking too much:
The proverb “empty vessel makes more noise”, will be the best match for this mistake. Likewise people will evaluate you to be an empty vessel when you talk more. Usage of short verbal conversation is always appreciated and welcomed every where.

3. To follow up basic verbal etiquette:
While conversing with others basic manners and etiquette has to be followed. The conversation will loose its values if it does not have mannered words in them.

4. Negative body language:
Negative body postures and signs make the listener irritant and unease to listen or communicate with. So to make the communication more brilliant negative body languages should be avoided.

5. Mastery over listener:
While having a conversation, avoid dominating your partner or listener. Give him/her the opportunity to share their opinion. Never go for a monologue way of conversation.

6. Interruption:

For a good communication, avoid interrupting in the middle when one person is talking. When a person is talking try to listen and understand and then ask excuse for the interrupting and then tell your suggestions or comments. Otherwise wait for him/her to finish and then share your thoughts.

7. Contradicting talks:
Never bring in contradiction during a conversation, especially when talking with the higher authorities or your own boss. This may cause unnecessary troubles and misunderstanding.

8. Poor contribution:
There are few people who listen and take information from others, but never contribute their suggestions. This is also a big communication mistake, because the communication again turns to monologue patterns.

9. Undesired advices:
There are people who give immediate advices for any problem told by others. So, the listener may again get restless and the communication is finally end. So, even while suggesting advices see that whether it is really required or not.

10. Loose talks:
Avoid talking unnecessary matters. Talk only to the pertained topic. This saves time and energy for both conversing people.

Tips to help you develop excellent oral communication skills

2008-12-31T13:49:00.000-08:00

1. Relax: If you think too much about an encounter, you'll likely freeze in the middle of the conversation and appear nervous. Going on a job interview and social gatherings evoke anxiety in many people. One way to overcome this problem is to stop worrying about how others may perceive you. It takes two people to have a meaningful conversation. Offer a smile, and confidently ask simple questions such as, "how are you," "are you having fun."

2. Use Humor: If you have a funny side to your personality, break the ice with a joke. Be tasteful. Everyone may not appreciate your sick sense of humor or crude jokes. You don't have to be the party clown, nor does your joke have to create a bellow of laughter.

3. Don't Monopolize the Conversation: When nervous, some people have the tendency to "shoot off at the mouth." In other words, they ramble uncontrollably. If trying to make a good first impression, don't talk too much. If the person asks you a simple question such as, "where are you from," offer a short 30 second answer. This is not an invitation to disclose you entire past, and talk for ten uninterrupted minutes. The person is probably not interested in where you attended elementary school, or the fact that you've lived in ten different cities.

4. Know When to End the Conversation: Person with poor communication skills dread the "awkward silence." If the conversation starts to die, you could casually change the topic and ask the person a question that's completely off subject; or you could simply say, it's been nice talking with you," and move on.

Bring your own conversation piece

If you're heading off to a party or get-together where you suspect that you won't know a lot of the other guests, it's a good idea to bring something with you that is highly likely to be a good conversation piece. If you're a hat person, choose one that has a great story that goes with it (or make one up on the way) and be prepared to tell people about it when they ask. Or wear an unusual accessory or piece of jewelry that will catch people's attention and compel them to ask you about it. If you're bringing a gift to a party, add an eye-catching flourish to the wrapping, which will stimulate some other creative soul to ask you about your original wrapping technique, or about the nature of the gift. Conversation pieces provide a non-threatening way to start a conversation.

Effectively, you're giving people an excuse to come and talk to you, by making yourself appear approachable and interesting because there's something about you that is an obvious talking point. You don't want to arrive looking bland and exactly like everyone else; you're trying to stimulate discussion, not a reaction of bored disinterest.

25 Words That Can Hurt Your C.V.'s Chance Of Success

2008-12-31T13:48:00.000-08:00

So, you're experienced? Before you advertise this in your C.V., be sure you can prove it.

Often, when job seekers try to sell themselves to potential employers, they load their C.V.s with vague claims that are transparent to recruiting managers, according to Scott Bennett, author of "The Elements of Resume Style" (published by AMACOM). By contrast, the most successful job seekers avoid these vague phrases on their C.V.s in favour of accomplishments.

Instead of making empty claims to demonstrate your work ethic, use brief, specific examples to demonstrate your skills. In other words, show, don't tell.

Bennett offers these examples:

Instead of... "Experience working in fast-paced environment"
Try... "Registered 120+ third-shift accident and emergency patients per night"

Instead of... "Excellent written communication skills"
Try... "Wrote jargon-free User Guide for 11,000 users"

Instead of... "Team player with cross-functional awareness"
Try... "Collaborated with clients, the Accounts Receivable Department and Sales to increase speed of receivables and prevent interruption of service to clients."

Instead of... "Demonstrated success in analysing client needs"
Try... "Created and implemented comprehensive needs assessment mechanism to help forecast demand for services and staffing."

The worst offenders
It’s good to be hard-working and ambitious, right? The recruiting manager won't be convinced if you can't provide solid examples to back up your claims. Bennett suggests being extremely careful before using these nice-sounding but empty words in your C.V.
· Aggressive
· Ambitious
· Competent
· Creative
· Detail-oriented
· Determined
· Efficient
· Experienced
· Flexible
· Goal-oriented
· Hard-working
· Independent
· Innovative
· Knowledgeable
· Logical
· Motivated
· Meticulous
· People person
· Professional
· Reliable
· Resourceful
· Self-motivated
· Successful
· Team player
· Well-organised

Why Should We Hire You?

2008-12-31T13:47:00.000-08:00

This is one of those broad questions that can take you down the wrong road unless you have done some thinking about what to say ahead of time. This question deals with your ability to sell yourself. Think of yourself as the product. Why should the customer buy?

Answers that WON'T WORK -
“Because I need a job.” – This answer is about YOU – “they” want to know what you can do for “them.”
“I am a hard worker.” – This is a really trite answer – almost anyone can say he or she is a hard worker.
“I saw your ad and could do the job. – This answers lacks passion and purpose.
STRONGER ANSWERS that would get the interviewer’s attention –
“Because I have three years experience working with customers in a very similar environment.”

“Because I have what it takes to fill the requirements of this job - solve customer problems using my excellent customer service skills.”

“Because I have the experience and expertise in the area of customer support that is required in this position.”

This is a time to let the customer (the interviewer) know what your product (YOU) can do for them and why they should listen to what you have to offer. The more detail you give the stronger your answer will be. This is not a time to talk about what you want.
It is a time to summarize your accomplishments and relate what makes you unique and therefore a viable fit for this position.

How To Improve Job Search Confidence?

2008-12-31T13:43:00.000-08:00

It’s very common for any (Many ) Job seeker to get frustrated moments and feel that how to improve confidence.
Let me ask you one question , what is confidence ?
How to measure that how much confidence any is having?
How to recognize that confidence is required ?
wait ,wait ,
just don’t think that I am going to enter a topic like philosophy and ask you what is Life ?
I just want to say you few feelings about the confidence. I feel every body will have same level of confidence . only the thing is at few times , it used to forget by the human. So it need to get back. But the confidence at the time of job search is not easy to get back , because it is tied up with many elements like money , prestige , surrounding people , etc . But among many , I want to choose the element of money. Because it makes any to independent up to some extent. The primary reason ,many used to said , what for job , is nothing but money. So lets concentrate on earning money. Is it tough to earn money ? No , not that much tough. It may be tough to earn money what extent any thinks to earn. But for basic needs , it’s not that much of tough to earn.

There are many part time jobs , these may not give the position what any dreams , but it gives little money and that gives the confidence. Those jobs may range from part time faculty to part time consultant . Try to get some job , at least for three months . So that some money you will get and few new people you can meet .so that you can able to get new issues and as well as you can develop your communication.

You may raise ask one more question .Will it won’t disturb my main job search ? am I not going to get deviated from the primary goal ? etc … BUT , I want to stress you one issue. If you really focus on your goal no body can change you. If you really feel to get , no body can stop you. I don’t want to give a big lectures about the motivation theories or self motivation techniques. I will say you , to know the world. Read the people. Means , try to understand what you require , then plan for it and get one by one. Don’t think that every thing you can make it in quick time.

I want to say one of the real problems I used to face. I , being an employer , really facing tremendous struggle to choose the right person to fill the position. It’s not that much of easy to fill a vacancy too. Many are not committed , many are not having subject , many are having not having communication , etc . I recommend you to meet as many people as possible for you , who are at good profession. try to get good tips from them. Try to analyze those , share with friends and decide what is your plan. The slowly implement it. if any problems you faced with that , try to revise it and continue it , till you win the job.

Confidence is not any where. It’s with you . You just try to get back that , by analyzing your self. Try to improve the knowledge in all positive issues. Try to read books or people. Stuff your self with knowledge. That gives you all. Don’t worry about communication (if you are lagging in it)/. Try to speak as much as possible , so that you can improve your communication level.

So get back your confidence. Be confident. Don’t leave your confidence after you get JOB, because life is not only for JOB.

All The Best !

All Basic Things About Java Script

2008-12-31T12:46:00.000-08:00

1. How to declare the methods in Javascript?

Methods are the actions that can be performed on objects.
Example:
script type=”text/javascript”>var str=”Hello world!”
document.write(str.toUpperCase())
In the above example UpperCase() method is used to print the string in Uppercases.

2. How do I print JavaScript output?
JavaScript programs cannot directly access printers. However, the user can print out everything on the Web page, including the output of JavaScript programs, by using the File | Print menu of the browser. How can I prevent an html page from being printed by a browser? Include a style sheet reference or a style sheet section with a media type of print. Set a rule for BODY with one entry, display:none.
3. Difference between Java Script and Vb Script?

Vb Script : Java Script :
1. Vb script will be run on IE
2. Vb script is developed by ms
3. Vb not case sensitive

1. Javascript runs on any browser
2. Java script by Sunmicrosystems
3. Java is case sensitive

4.How can JavaScript make a Web site easier to use? That is, are there certain JavaScript techniques that make it easier for people to use a Web site?

JavaScript's greatest potential gift to a Web site is that scripts can make the page more immediately interactive, that is, interactive without having to submit every little thing to the server for a server program to re-render the page and send it back to the client.

For example, consider a top-level navigation panel that has, say, six primary image map links into subsections of the Web site. With only a little bit of scripting, each map area can be instructed to pop up a more detailed list of links to the contents within a subsection whenever the user rolls the cursor atop a map area.

With the help of that popup list of links, the user with a scriptable browser can bypass one intermediate menu page.
The user without a scriptable browser (or who has disabled JavaScript) will have to drill down through a more traditional and time-consuming path to the desired content.

Operating Systems Interview Questions

2008-12-31T04:34:00.001-08:00

* What is MUTEX ?
* What isthe difference between a 'thread' and a 'process'?
* What is INODE?
* Explain the working of Virtual Memory.
* How does Windows NT supports Multitasking?
* Explain the Unix Kernel.
* What is Concurrency? Expain with example Deadlock and Starvation.
* What are your solution strategies for "Dining Philosophers Problem" ?
* Explain Memory Partitioning, Paging, Segmentation.
* Explain Scheduling.
* Operating System Security.
* What is Semaphore?
* Explain the following file systems : NTFS, Macintosh(HPFS), FAT .
* What are the different process states?
* What is Marshalling?
* Define and explain COM?
* What is Marshalling?
* Difference - Loading and Linking ?
* What are the basic functions of an operating system?
* Explain briefly about, processor, assembler, compiler, loader, linker and the functions executed by them.
* What are the difference phases of software development? Explain briefly?
* Differentiate between RAM and ROM?
* What is DRAM? In which form does it store data?
* What is cache memory?
* What is hard disk and what is its purpose?
* Differentiate between Complier and Interpreter?
* What are the different tasks of Lexical analysis?
* What are the different functions of Syntax phase, Sheduler?
* What are the main difference between Micro-Controller and Micro- Processor?
* Describe different job scheduling in operating systems.
* What is a Real-Time System ?
* What is the difference between Hard and Soft real-time systems ?
* What is a mission critical system ?
* What is the important aspect of a real-time system ?
* If two processes which shares same system memory and system clock in a distributed system, What is it called?
* What is the state of the processor, when a process is waiting for some event to occur?
* What do you mean by deadlock?
* Explain the difference between microkernel and macro kernel.
* Give an example of microkernel.
* When would you choose bottom up methodology?
* When would you choose top down methodology?
* Write a small dc shell script to find number of FF in the design.
* Why paging is used ?
* Which is the best page replacement algorithm and Why? How much time is spent usually in each phases and why?
* Difference between Primary storage and secondary storage?
* What is multi tasking, multi programming, multi threading?
* Difference between multi threading and multi tasking?
* What is software life cycle?
* Demand paging, page faults, replacement algorithms, thrashing, etc.
* Explain about paged segmentation and segment paging
* While running DOS on a PC, which command would be used to duplicate the entire diskette?
Following are a few basic questions that cover the essentials of OS:

1. When is a system in safe state?
The set of dispatchable processes is in a safe state if there exists at least one temporal order in which all processes can be run to completion without resulting in a deadlock.

2. What is cycle stealing?
We encounter cycle stealing in the context of Direct Memory Access (DMA). Either the DMA controller can use the data bus when the CPU does not need it, or it may force the CPU to temporarily suspend operation. The latter technique is called cycle stealing. Note that cycle stealing can be done only at specific break points in an instruction cycle.

3. What is meant by arm-stickiness?
If one or a few processes have a high access rate to data on one track of a storage disk, then they may monopolize the device by repeated requests to that track. This generally happens with most common device scheduling algorithms (LIFO, SSTF, C-SCAN, etc). High-density multisurface disks are more likely to be affected by this than low density ones.

4. What are the stipulations of C2 level security?
C2 level security provides for:
> Discretionary Access Control
> Identification and Authentication
> Auditing
> Resource reuse

5. What is busy waiting?
The repeated execution of a loop of code while waiting for an event to occur is called busy-waiting. The CPU is not engaged in any real productive activity during this period, and the process does not progress toward completion.

6. What are short-, long- and medium-term scheduling?
Long term scheduler determines which programs are admitted to the system for processing. It controls the degree of multiprogramming. Once admitted, a job becomes a process.
Medium term scheduling is part of the swapping function. This relates to processes that are in a blocked or suspended state. They are swapped out of real-memory until they are ready to execute. The swapping-in decision is based on memory-management criteria.
Short term scheduler, also know as a dispatcher executes most frequently, and makes the finest-grained decision of which process should execute next. This scheduler is invoked whenever an event occurs. It may lead to interruption of one process by preemption.

Following are a few basic questions that cover the essentials of OS:

1. Explain the concept of Reentrancy.
It is a useful, memory-saving technique for multiprogrammed timesharing systems. A Reentrant Procedure is one in which multiple users can share a single copy of a program during the same period. Reentrancy has 2 key aspects: The program code cannot modify itself, and the local data for each user process must be stored separately. Thus, the permanent part is the code, and the temporary part is the pointer back to the calling program and local variables used by that program. Each execution instance is called activation. It executes the code in the permanent part, but has its own copy of local variables/parameters. The temporary part associated with each activation is the activation record. Generally, the activation record is kept on the stack.
Note: A reentrant procedure can be interrupted and called by an interrupting program, and still execute correctly on returning to the procedure.

2. Explain Belady's Anomaly.
Also called FIFO anomaly. Usually, on increasing the number of frames allocated to a process' virtual memory, the process execution is faster, because fewer page faults occur. Sometimes, the reverse happens, i.e., the execution time increases even when more frames are allocated to the process. This is Belady's Anomaly. This is true for certain page reference patterns.

3. What is a binary semaphore? What is its use?
A binary semaphore is one, which takes only 0 and 1 as values. They are used to implement mutual exclusion and synchronize concurrent processes.

4. What is thrashing?
It is a phenomenon in virtual memory schemes when the processor spends most of its time swapping pages, rather than executing instructions. This is due to an inordinate number of page faults.

5. List the Coffman's conditions that lead to a deadlock.
Ø Mutual Exclusion: Only one process may use a critical resource at a time.
Ø Hold & Wait: A process may be allocated some resources while waiting for others.
Ø No Pre-emption: No resource can be forcible removed from a process holding it.
Ø Circular Wait: A closed chain of processes exist such that each process holds at least one resource needed by another process in the chain.

6. What are short-, long- and medium-term scheduling?
Long term scheduler determines which programs are admitted to the system for processing. It controls the degree of multiprogramming. Once admitted, a job becomes a process.
Medium term scheduling is part of the swapping function. This relates to processes that are in a blocked or suspended state. They are swapped out of real-memory until they are ready to execute. The swapping-in decision is based on memory-management criteria.
Short term scheduler, also know as a dispatcher executes most frequently, and makes the finest-grained decision of which process should execute next. This scheduler is invoked whenever an event occurs. It may lead to interruption of one process by preemption.

7. What are turnaround time and response time?
Turnaround time is the interval between the submission of a job and its completion. Response time is the interval between submission of a request, and the first response to that request.

8. What are the typical elements of a process image?
Ø User data: Modifiable part of user space. May include program data, user stack area, and programs that may be modified.
Ø User program: The instructions to be executed.
Ø System Stack: Each process has one or more LIFO stacks associated with it. Used to store parameters and calling addresses for procedure and system calls.
Ø Process control Block (PCB): Info needed by the OS to control processes.

9. What is the Translation Lookaside Buffer (TLB)?
In a cached system, the base addresses of the last few referenced pages is maintained in registers called the TLB that aids in faster lookup. TLB contains those page-table entries that have been most recently used. Normally, each virtual memory reference causes 2 physical memory accesses-- one to fetch appropriate page-table entry, and one to fetch the desired data. Using TLB in-between, this is reduced to just one physical memory access in cases of TLB-hit.

10. What is the resident set and working set of a process?
Resident set is that portion of the process image that is actually in real-memory at a particular instant. Working set is that subset of resident set that is actually needed for execution. (Relate this to the variable-window size method for swapping techniques.)

11. When is a system in safe state?
The set of dispatchable processes is in a safe state if there exists at least one temporal order in which all processes can be run to completion without resulting in a deadlock.

12. What is cycle stealing?
We encounter cycle stealing in the context of Direct Memory Access (DMA). Either the DMA controller can use the data bus when the CPU does not need it, or it may force the CPU to temporarily suspend operation. The latter technique is called cycle stealing. Note that cycle stealing can be done only at specific break points in an instruction cycle.

13. What is meant by arm-stickiness?
If one or a few processes have a high access rate to data on one track of a storage disk, then they may monopolize the device by repeated requests to that track. This generally happens with most common device scheduling algorithms (LIFO, SSTF, C-SCAN, etc). High-density multisurface disks are more likely to be affected by this than low density ones.

14. What are the stipulations of C2 level security?
C2 level security provides for:
Ø Discretionary Access Control
Ø Identification and Authentication
Ø Auditing
Ø Resource reuse

15. What is busy waiting?
The repeated execution of a loop of code while waiting for an event to occur is called busy-waiting. The CPU is not engaged in any real productive activity during this period, and the process does not progress toward completion.

16. Explain the popular multiprocessor thread-scheduling strategies.
Ø Load Sharing: Processes are not assigned to a particular processor. A global queue of threads is maintained. Each processor, when idle, selects a thread from this queue. Note that load balancing refers to a scheme where work is allocated to processors on a more permanent basis.
Ø Gang Scheduling: A set of related threads is scheduled to run on a set of processors at the same time, on a 1-to-1 basis. Closely related threads / processes may be scheduled this way to reduce synchronization blocking, and minimize process switching. Group scheduling predated this strategy.
Ø Dedicated processor assignment: Provides implicit scheduling defined by assignment of threads to processors. For the duration of program execution, each program is allocated a set of processors equal in number to the number of threads in the program. Processors are chosen from the available pool.
Ø Dynamic scheduling: The number of thread in a program can be altered during the course of execution.

17. When does the condition 'rendezvous' arise?
In message passing, it is the condition in which, both, the sender and receiver are blocked until the message is delivered.

18. What is a trap and trapdoor?
Trapdoor is a secret undocumented entry point into a program used to grant access without normal methods of access authentication. A trap is a software interrupt, usually the result of an error condition.

19. What are local and global page replacements?
Local replacement means that an incoming page is brought in only to the relevant process' address space. Global replacement policy allows any page frame from any process to be replaced. The latter is applicable to variable partitions model only.

20. Define latency, transfer and seek time with respect to disk I/O.
Seek time is the time required to move the disk arm to the required track. Rotational delay or latency is the time it takes for the beginning of the required sector to reach the head. Sum of seek time (if any) and latency is the access time. Time taken to actually transfer a span of data is transfer time.

22. What is time-stamping?
It is a technique proposed by Lamport, used to order events in a distributed system without the use of clocks. This scheme is intended to order events consisting of the transmission of messages. Each system 'i' in the network maintains a counter Ci. Every time a system transmits a message, it increments its counter by 1 and attaches the time-stamp Ti to the message. When a message is received, the receiving system 'j' sets its counter Cj to 1 more than the maximum of its current value and the incoming time-stamp Ti. At each site, the ordering of messages is determined by the following rules: For messages x from site i and y from site j, x precedes y if one of the following conditions holds....(a) if Ti<Tj or (b) if Ti=Tj and i<j.

23. How are the wait/signal operations for monitor different from those for semaphores?
If a process in a monitor signal and no task is waiting on the condition variable, the signal is lost. So this allows easier program design. Whereas in semaphores, every operation affects the value of the semaphore, so the wait and signal operations should be perfectly balanced in the program.

24. In the context of memory management, what are placement and replacement algorithms?
Placement algorithms determine where in available real-memory to load a program. Common methods are first-fit, next-fit, best-fit. Replacement algorithms are used when memory is full, and one process (or part of a process) needs to be swapped out to accommodate a new program. The replacement algorithm determines which are the partitions to be swapped out.

25. In loading programs into memory, what is the difference between load-time dynamic linking and run-time dynamic linking?
For load-time dynamic linking: Load module to be loaded is read into memory. Any reference to a target external module causes that module to be loaded and the references are updated to a relative address from the start base address of the application module.
With run-time dynamic loading: Some of the linking is postponed until actual reference during execution. Then the correct module is loaded and linked.

26. What are demand- and pre-paging?
With demand paging, a page is brought into memory only when a location on that page is actually referenced during execution. With pre-paging, pages other than the one demanded by a page fault are brought in. The selection of such pages is done based on common access patterns, especially for secondary memory devices.

27. Paging a memory management function, while multiprogramming a processor management function, are the two interdependent?
Yes.

28. What is page cannibalizing?
Page swapping or page replacements are called page cannibalizing.

29. What has triggered the need for multitasking in PCs?
Increased speed and memory capacity of microprocessors together with the support fir virtual memory and
Growth of client server computing

30. What are the four layers that Windows NT have in order to achieve independence?
Hardware abstraction layer
Kernel
Subsystems
System Services.

31. What is SMP?
To achieve maximum efficiency and reliability a mode of operation known as symmetric multiprocessing is used. In essence, with SMP any process or threads can be assigned to any processor.

32. What are the key object oriented concepts used by Windows NT?
Encapsulation
Object class and instance

33. Is Windows NT a full blown object oriented operating system? Give reasons.
No Windows NT is not so, because its not implemented in object oriented language and the data structures reside within one executive component and are not represented as objects and it does not support object oriented capabilities .

34. What is a drawback of MVT?
It does not have the features like
ability to support multiple processors
virtual storage
source level debugging

35. What is process spawning?
When the OS at the explicit request of another process creates a process, this action is called process spawning.

36. How many jobs can be run concurrently on MVT?
15 jobs

37. List out some reasons for process termination.
Normal completion
Time limit exceeded
Memory unavailable
Bounds violation
Protection error
Arithmetic error
Time overrun
I/O failure
Invalid instruction
Privileged instruction
Data misuse
Operator or OS intervention
Parent termination.

38. What are the reasons for process suspension?

1. swapping
2. interactive user request
3. timing
4. parent process request

39. What is process migration?
It is the transfer of sufficient amount of the state of process from one machine to the target machine

40. What is mutant?
In Windows NT a mutant provides kernel mode or user mode mutual exclusion with the notion of ownership.

41. What is an idle thread?
The special thread a dispatcher will execute when no ready thread is found.

42. What is FtDisk?
It is a fault tolerance disk driver for Windows NT.

43. What are the possible threads a thread can have?
Ø Ready
Ø Standby
Ø Running
Ø Waiting
Ø Transition
Ø Terminated.

44. What are rings in Windows NT?
Windows NT uses protection mechanism called rings provides by the process to implement separation between the user mode and kernel mode.

45. What is Executive in Windows NT?
In Windows NT, executive refers to the operating system code that runs in kernel mode.

46. What are the sub-components of I/O manager in Windows NT?
Ø Network redirector/ Server
Ø Cache manager.
Ø File systems
Ø Network driver
Ø Device driver

47. What are DDks? Name an operating system that includes this feature.
DDks are device driver kits, which are equivalent to SDKs for writing device drivers. Windows NT includes DDks.

48. What level of security does Windows NT meets?
C2 level security.

Java/J2ME Interview Questions

2008-12-31T04:32:00.000-08:00

1.) Difference between Enumeration and Iteration?

Both will help you to travel into collection bag, but Enumeration is a legacy classes, Iterator have introduced in Collection framework. In enumeration we can modify the collection objects but throw Iterator it is possible. Enumeration can be used for Collection objects as well as Iterator can be used for legacy classes. Enumeration acts as Read-only interface, where as using Iterator we can manipulate the objects also like adding and removing the objects. So Enumeration is used whenever we want to make Collection objects as Read-only.

2.) What’s the difference between Transient and Volatile?

Transient: The transient modifier applies to variables only and it is not stored as part of its object’s Persistent state. These variables are not serialized. Transient instance fields are neither saved nor restored by the standard serialization. You have to handle restoring them yourself.

Volatile: Volatile modifier tells the compiler that the variable modified by volatile can be changed unexpectedly by other parts of the program. For example a Variable might be read from Cache and not update the content if it has been changed by another thread. Specifying a variable as volatile tells the JVM that any threads using that variable are not allowed to cache that value at all. Making the Variable Volatile will ensure that the compiler will get the content of the variable every time it is used and not cache its content. If not used Carefully this modifier might introduce bugs.

3.) Is JVM platform dependent?

Although java is platform independent but still JVM IS platform dependent one of the feature called byte code makes JVM platform dependent. Byte code is an intermediate machine code of compiled source code. The byte code can run on all machines, however the JVM must be installed in each machine.

4.) What are wrapper classes? Why do we need wrapper classes?

Java provides specialized classes corresponding to each of the primitive data types. These are called wrapper classes. They are Boolean, Byte, Character, Double, Float, Integer, Long, and Short.

We can create instances of these classes hence we can store them in any of the collection classes and pass them around as a collection. Also we can pass them around as method parameters where a method expects an object.

5.) What are Checked and Unchecked Exception?

A checked exception is generally known as Compiletime Exception. Checked exception forces client programmers to deal with the possibility that the exception will be thrown hence the programmer has to handle these types of exceptions. e.g., IOException thrown by java.io.FileInputStream’s read( ) method.

Where as Unchecked exceptions are Runtime Exception. With an unchecked exception, however, the compiler doesn’t force client programmers either to catch the exception or declare it in a throws clause. In fact, client programmers may not even know that the exception could be thrown. e.g., StringIndexOutOfBounds Exception thrown by String’s charAt () method· Checked exceptions must be caught at compile time but Runtime exceptions do not need to be.

6.) What is deadlock and how it can be avoid?

Deadlock is a situation when two threads are waiting on each other to release a resource. Each thread waiting for a resource, which is held by the other waiting thread. In Java, this resource is usually the object lock obtained by the synchronized keyword.

7.) What is the difference between interface and abstract class?

Difference between interface and abstract:
All the methods declared inside interface should be abstract, and there is no need to use the key word “abstract” for those method, but in case of abstract class at least one method should be abstract, most importantly u have to use the “abstract” key word for that method, besides that it may contain concrete methods. Abstract class must be extended abstract () methods generally contain only declaration part without definition part.

8.) Why are there no global variables in Java?

Global variables are considered bad form for a variety of reasons:

* Adding state variables breaks referential transparency (you no longer can understand a statement or expression on its own: you need to understand it in the context of the settings of the global variables).
* State variables lessen the cohesion of a program: you need to know more to understand how something works. A major point of Object-Oriented programming is to break up global state into more easily understood collections of local state.
* When you add one variable, you limit the use of your program to one instance. What you thought was global, someone else might think of as local: they may want to run two copies of your program at once.

9.) What are the steps in the JDBC connection?

For making a JDBC connection we need to go through the following steps:

Step 1: Register the database driver by using:
Class.forName (\” driver class for that specific database\”);

Step 2 : Create a database connection using:
Connection con = DriverManager.getConnection (url, username, password);

Step 3: Create a query using:
Statement stmt = Connection.Statement (\”select * from TABLE NAME\”);

Step 4: Exceute the query:
Stmt.exceuteUpdate ();

10.) What is an enumeration?

An enumeration is an interface which containing methods for accessing the underlying data structure. It is a construct which collection classes return when you request a collection of all the objects stored in the collection. It allows sequential access to all the elements stored in the collection.

11.) How Application is differ from Applet?

Applications:

* Applications are Stand Alone and the doesn’t need web-browser.
* Execution of Applications starts with main ().

Applets:

* Needs no explicit installation on local machine. Can be transferred through Internet on to the local machine and may run as part of web-browser.
* Execution Applets starts with init () method and it must run within a GUI, it may be AWT / Swing.

12.) What is CDC?

The Connected Device Configuration (CDC) is a specification for a J2ME configuration. Conceptually, CDC deals with devices with more memory and processing power than CLDC; it is for devices with an always-on network connection and a minimum of 2 MB of memory available for the Java system.

13.) What is the MIDP?

The MIDP defines a set of APIs for mobile devices, such as cell phones and low-end PDAs

14.) What is variable typing in javascript?

It is perfectly legal to assign a number to a variable and then assign a string to the same variable as follows

Example: i = 10;

i = “string”;

15.) What does a well-written java program look like?

A well-written java program exhibits recurring structures that promote abstraction, flexibility, modularity and elegance.

Interview Tips

2008-12-31T04:31:00.000-08:00

These days, interviews don't come easily. When you get The Call, make the most of your time -- and go for it!

1. Investigate the company's culture, markets, and finances. But resist the temptation to show off what you've researched: "I just read that you're about to embark on a new product line") unless you have a question directly related to your career.

2. Look like you belong. Learn the company's dress code and err on the side of conservatism. When you're seeking a senior position based on industry experience, you'll be expected to know the rules without being told.

3. Take charge of the interview! The most successful interviews feel like friendly conversations. When your interviewer has an agenda (such as the infamous "stress interview") stay relaxed. Think of playing a game.

4. Assume everyone you meet will provide feedback to the decision-maker. Some companies hand out comment forms to receptionists, security guards and potential peers who take you to lunch.

5. Communicate interest and enthusiasm, even if you're not sure you're ready to commit. You'll rarely have all the facts until you're looking at an offer.

6. Bring extra copies of your correspondence from this company as well as your resume, references, writing
samples, portfolio and current business cards. Interviewers lose documents and conversations move in unexpected directions.

7. Create a relaxed, positive attitude by devising a realistic game plan. When your career isn't riding on a single interview, you'll have fun and make a confident, relaxed impression.

8. Write a thank you letter within forty-eight hours. Create a low-key sales letter, emphasizing how your qualifications match the company's needs. Present yourself as a resource, not a supplicant.

9. After you write the letter, forget about the interview. Email or phone only if you've received a competing offer with a deadline.

Occasionally you may make points with follow-up mailings. A sports team public relations applicant sent puzzles, games and press releases -- and she got the job. Use your intuition.

10. Keep notes of what you learned from the process. What worked? What would you do differently?
As soon as you begin your new job, develop a career plan and a safety net before you need one.

What mistakes you need to avoid for better English?

2008-12-31T04:30:00.000-08:00

You can learn English without any mistakes, How? You should fill your brain with correct sentences and imitate them.

To avoid mistakes you can follow some books dictionary,or you can listen native speaker’s language.If you practice seriously then it is very hard to make a mistake! First, try to be more careful by using the rules of error free speaking. If you still make a lot of mistakes , more than 1 mistake every 3 sentences, try to practice by reading and listening in English. You avoid mistakes if you follow a couple of rules:

Try to use very simple language
Some beginners try to build very complicated sentences with things like the present perfect tense or conditionals. They make horrible mistakes. Don't do this!First use some simple sententences and they try complecated. If you've just started to speak or write in English it would be very difficult to use complecated sentences.More chances are there to make mistakes.You may feel you're talking like a child or that you are not expressing your thoughts, but don't worry about it. Right now, your task is not to express your thoughts freely; your task is to learn the language.

Be slow and careful
In the beginning, you should write very slowly. If you need 2 hours to write an e-mail message with 10 correct sentences, that's okay. That's how long it should take if you're just starting to write. Why should it take so long? Because you should read your sentences many times, looking for mistakes. You should correct your own sentences frequently. You should check if your sentences are correct by using a dictionary and the Web. And you should look for example sentences to imitate. If you are more care ful you can avoid mistakes.

If you're not sure how to say something, don't say it
Some times when you speak, you can't say something correctly, it's almost better not to say it.Otherwise you will make some mistakes. You don't want to teach yourself the wrong way to say it. Instead of that you can try to look for the correct sentence in a dictionary or on the Web. But when speaking, usually you don't have time for that. So it's a good idea to say something else — something that you know is correct. It can even be something on a different subject.

When writing, always look things up
Whenever you're not sure how to use a word, look it up in a good dictionary to find example sentences with it. When you've written something, and you are not sure if it's correct, search for it on the Web . If many pages contain your phrase, then it is probably correct. Dictionaries and web should be your everyday tools, and you should use them even many times in one sentence.If you do so you will get the idea how to use dictionary and web.

Know where you can screw up
Sometimes learners can not realize how different English is from their native language. When speaking, they translate word for word from their native language, and they think their sentences are okay. When reading or listening in English, pay close attention to things like word order, articles, prepositions, and tenses. Compare sentences in English with equivalent sentences in your native language. Notice the differences in words and in word order. This will make you more careful when speaking in the foreign language, because you will realize which parts of your sentences can be wrong and should be double-checked.

Don't worry about fluency
Fluency is easy to achieve by simply talking. If you practice speaking, you will be able to speak faster and faster Through practice you can achieve fluency.You should be very slow and correct ,while you speak,you can easily improve your fluency.But if you are fluent and make a lot of mistakes, it is not so easy to remove your mistakes and become fluent and correct. So you should speak slowly without making any mistakes and gadually you can attain fluency.

Don't speak or write too early
First write, then speak.
Writing is easier than speaking because:
1) you don't need to have good pronunciation,but you need good spelling
2) you can write very slowly and nobody will mind
3) you can use dictionaries, the Web, etc. So, it's a good idea to practice writing first until you can build correct sentences quickly enough for speaking.

Don't speak until you've learned to pronounce English sounds
You need to be able to pronounce all the English vowels and consonants in a clear way before you speak. If you don't, you will get used to bad pronunciation.

Don't say a word if you don't know how to pronounce it
In other words, you need to know the pronunciation of all the words that you use. If you don't, you will be making pronunciation mistakes and teaching yourself bad habits.

Remember that you should first get lots of English sentences into your head, then build your own sentences. Your main activity should be reading and listening to English and you will get more examples to follow before you can build your own sentences. The more sentences your brain absorbs, the more you can express in English. If you don't hear enough correct, natural English sentences, you will not know how to say things in English. So you will be inventing your own language. And you will be making mistakes.

A Student's Guide to Interviewing With Third-Party Recruiters

2008-12-31T04:29:00.001-08:00

As you conduct your job search you will find that some employers hire third-party organizations to assist them in identifying and hiring college students. An employer can hire a third-party organization to do on-campus recruiting, represent the company at a job fair, screen job candidates who apply through an Internet web site, or other hiring activities. Many college career centers allow third-party recruiters to work with students through their offices. Some have special policies that apply to how, when, and where third-party recruiters can work with students. Check with your career center for more information.

The National Association of Colleges and Employers (NACE) defines third-party recruiters as "agencies, organizations, or individuals recruiting candidates for temporary, part-time, or full-time employment opportunities other than for their own needs." Categories of third-party recruiters include:

* Employment Agencies: Employment agencies list positions for a number of organizations and receive payment when a referred candidate is hired. The fee for listing a position is paid either by the firm listing the opening or by the candidate who is hired. If the job listing does not include the phrase "fee paid," be sure to ask who pays the fee before signing any papers.
* Search Firms: A search firm contracts with employers to find and screen qualified persons to fill specific positions. The fee is paid by the employer. Search firm representatives will identify the employer they represent.
* Contract Recruiters: Employers hire contract recruiters to represent them in the recruiting and employment function.
* Resume Referral Firms: A resume referral firm collects information on job seekers and forwards it to prospective employers. Data can be contained in resumes or on data forms (either paper or electronic). The employer, job seeker, or both may pay fees. You must give the firm written permission to pass your resume to employers. Your permission should include a statement that expressly states to whom and for what purpose the information can be used.

Questions to Ask

A third-party recruiter may be helpful to you in your job search, but be a wise consumer. Read all materials carefully. Ask questions. Ask your career services office staff for information. Ask a lawyer to read any contracts you are asked to sign. Here are some general questions you may want to ask:

1. How many job openings are there for someone in my field? If you have the opportunity, inquire about the positions being filled or the number of openings related to your field. These are important questions because, in some instances, recruiters may not really have the type or number of openings they advertise. They may be more interested in adding your name to their candidate pool as a means of attracting more employers or clients to their services. Or they may be collecting resumes from students for potential job opportunities. Your school may or may not not allow third-party recruiters to interview students unless they are trying to fill actual job openings.
2. How is this information being used? A third-party recruiter is allowed legally to share your resume with the contract employer for positions that you are actually seeking. The recruiter must tell you, in clear terms, that your materials and information will not be shared outside the organization or used for any purpose other than with the company they represent at the time they interview you. The third-party recruiter cannot sell your information to anyone else. You may choose to authorize the recruiter to share your data elsewhere, but your authorization should be given to the recruiter in writing.
3. Are candidates treated equally and fairly? If you are qualified for the job opportunity, the third-party recruiter must pass your information to employers without regard to your race, color, national origin, religion, age, gender, sexual orientation, or disability.
4. Who pays the fee? Before you agree to anything or sign a contract, ask the recruiter who will pay the fee.

For assistance with these questions or other related topics, contact the career center on your college or university campus.

C / C++ - Frequently Asked Questions

2008-12-31T04:22:00.000-08:00

1.) How To Split an Image File In C Launguage?

To split an image file various logics are there.the best logic in such a way that take the size of the file using c file functions and split into the pieces how many required by asking the input.

2.)What is the difference between an ARRAY and a LIST?

Array is collection of homogeneous elements. List is collection of heterogeneous elements. For Array memory allocated is static and continuous. For List memory allocated is dynamic and Random. Array: User need not have to keep in track of next memory allocation. List: User has to keep in Track of next location where memory is allocated.

3.)Define a constructor - what it is and how it might be called?

constructor is a member function of the class, with the name of the function being the same as the class name. It also specifies how the object should be initialized

4.)Define a constructor - what it is and how it might be called?

constructor is a member function of the class, with the name of the function being the same as the class name. It also specifies how the object should be initialized Ways of calling constructor:
1) Implicitly: automatically by complier when an object is created.
2) Calling the constructors explicitly is possible, but it makes the code unverifiable.

5.)You have two pairs: new() and delete() and another pair : alloc() and free(). Explain differences between eg. new() and malloc()?

1.) “new and delete” are preprocessors while “malloc() and free()” are functions. [we dont use brackets will calling new or delete].
2.) no need of allocate the memory while using “new” but in “malloc()” we have to use “sizeof()”.
3.) “new” will initlize the new memory to 0 but “malloc()” gives random value in the new alloted memory location [better to use calloc()].

6.)Explain term POLIMORPHISM?

POLYMORPHISM : A phenomenon which enables an object to react differently to the same function call. in C++ it is attained by using a keyword virtual

7.)What are 2 ways of exporting a function from a DLL?

1.Taking a reference to the function from the DLL instance.
2. Using the DLL ’s Type Library

8.)Describe PRIVATE, PROTECTED and PUBLIC – the differences?

The Difference Between The private Public And Protected member are: public methods/attributes are accessible to all classes. protected are accessible to class and derived classes. private are only for class (not for derived classes)

A-Z of English Communication for Job Seekers

2008-12-31T04:21:00.000-08:00

Communication is the successful transmission of information through a common system of symbols, signs, behavior, speech, writing, or signals.

Communication is essentially the transfer of ideas, messages or information from one person to another. It is effective when it gets the desired action or response. Basic communication skills are essential for continued success, whether personal or professional. At the very base one needs to understand the communication process.

Since effective communication is essential for success, you have to make an all-out effort to improve your communication skills. To do so, job seekers and others those who have interest to enhance their communication skills can take the following course.

1. To communicate your response, you have to understand the point being made in the question. To understand, you have to listen carefully. Listening is the key to your understanding.

2. Plan and conceptualize your thoughts before giving a response. This requires your ability quickly and focuses on the core point. You may take a moment’s pause to compose your thoughts before answering, but think before you answer.

3. Sharpen your language skills. Use simple words and short sentences as far as possible. Strictly avoid long sentences, which can confuse and make you lose track of your talking points. Reading articles and books can help a candidate improve his language skill and participate effectively in the communication process.

4. Remove the fear of failure from the mind. Look at the silver lining of the cloud. One failure may be a learning point for success in the next interview. The world is not lost with one failure in an interview, as long as you are open to learning from the experience. So, take it easy.

5. Perceive rightly. Be rational and don’t rush into a judgment without analyzing the message. Try to perceive the message from the point of view of the sender.

6. Make it a habit to put down thoughts on a piece of paper, if you are not comfortable with mental conceptualization. Then, try to verbalize them.

7. Avoid needless communication. It takes away your valuable time and also tends to expose your inconsistency. Answer to the point with relevant information, and do not resort to long elaboration.

8. Be mindful about the body language of the receiver. Quite often, the interviewer’s body language conveys the signal about your effectiveness and correctness of answer. It will also tell you when to stop. If you don’t stop soon, you may be at a disadvantage.

Facilitating Communication

In addition to removal of specific barriers to communication, the following general Guidelines may also facilitate communication.

1. Have a positive attitude about communication. Defensiveness interferes with Communication.
2. Work at improving communication skills. It takes knowledge and work. The communication model and discussion of barriers to communication provide the necessary knowledge. This increased awareness of the potential for improving communication is the first step to better communication.

3. Include communication as a skill to be evaluated along with all the other skills in each person's job description. Help other people improve their communication skills by helping them understand their communication problems.

4. Make communication goal oriented. Relational goals come first and pave the way for other goals. When the sender and receiver have a good relationship, they are much more likely to accomplish their communication goals.

5. Approach communication as a creative process rather than simply part of the chore of working with people. Experiment with communication alternatives. What works with one person may not work well with another person. Vary channels, listening techniques, and feedback techniques.

6. Accept the reality of miscommunication. The best communicators fail to have perfect Communication. They accept miscommunication and work to minimize its negative impacts.

Communication is at the heart of many interpersonal problems faced by farm employers. Understanding the communication process and then working at improvement provide managers a recipe for becoming more effective communicators. Knowing the common barriers to communication is the first step to minimizing their impact. Managers can reflect on how they are doing and make use of the ideas presented in this paper. When taking stock of how well you are doing as a manager, first ask yourself and others how well you are doing as a communicator.

Aptitude Questions and Answers

2008-12-31T04:19:00.001-08:00

If 2x-y=4 then 6x-3y=?

(a)15
(b)12
(c)18
(d)10

Ans. (b)

If x=y=2z and xyz=256 then what is the value of x?

(a)12
(b)8
(c)16
(d)6

Ans. (b)

Pipe A can fill in 20 minutes and Pipe B in 30 mins and Pipe C can empty the same in 40 mins. If all of them work together, find the time taken to fill the tank

(a) 17 1/7 mins
(b) 20 mins
(c) 8 mins
(d) none of these

Ans. (a)

Thirty men take 20 days to complete a job working 9 hours a day. How many hour a day should 40 men work to complete the job?

(a) 8 hrs
(b) 7 1/2 hrs
(c) 7 hrs
(d) 9 hrs

Ans. (b)

Find the smallest number in a GP whose sum is 38 and product 1728

(a) 12
(b) 20
(c) 8
(d) none of these

Ans. (c)

A boat travels 20 kms upstream in 6 hrs and 18 kms downstream in 4 hrs. Find the speed of the boat in still water and the speed of the water current?

(a) 1/2 kmph
(b) 7/12 kmph
(c) 5 kmph
(d) none of these

Ans. (b)

A goat is tied to one corner of a square plot of side 12m by a rope 7m long. Find the area it can graze?

(a) 38.5 sq.m
(b) 155 sq.m
(c) 144 sq.m
(d) 19.25 sq.m

Ans. (a)

Mr. Shah decided to walk down the escalator of a tube station. He found that if he walks down 26 steps, he requires 30 seconds to reach the bottom. However, if he steps down 34 stairs he would only require 18 seconds to get to the bottom. If the time is measured from the moment the top step begins to descend to the time he steps off the last step at the bottom, find out the height of the stair way in steps?

Ans.46 steps.

The average age of 10 members of a committee is the same as it was 4 years ago, because an old member has been replaced by a young member. Find how much younger is the new member ?

Ans.40 years.

ABCE is an isosceles trapezoid and ACDE is a rectangle. AB = 10 and EC = 20. What is the length of AE?

Ans. AE = 10.

In the given figure, PA and PB are tangents to the circle at A and B respectively and the chord BC is parallel to tangent PA. If AC = 6 cm, and length of the tangent AP is 9 cm, then what is the length of the chord BC?

Ans. BC = 4 cm.

Three cards are drawn at random from an ordinary pack of cards. Find the probability that they will consist of a king, a queen and an ace.

Ans. 64/2210.

A number of cats got together and decided to kill between them 999919 mice. Every cat killed an equal number of mice. Each cat killed more mice than there were cats. How many cats do you think there were ?

Ans. 991.

If Log2 x - 5 Log x + 6 = 0, then what would the value / values of x be?

Ans. x = e2 or e3.

The square of a two digit number is divided by half the number. After 36 is added to the quotient, this sum is then divided by 2. The digits of the resulting number are the same as those in the original number, but they are in reverse order. The ten's place of the original number is equal to twice the difference between its digits. What is the number?

Ans. 46

Can you tender a one rupee note in such a manner that there shall be total 50 coins but none of them would be 2 paise coins.?

Ans. 45 one paisa coins, 2 five paise coins, 2 ten paise coins, and 1 twenty-five paise coins.

20 Job Interview Success Tips

2008-12-31T04:15:00.000-08:00

1. Get references and letters of recommendation. Think of three to six professional
associates (i.e., co-workers, former bosses) who you believe will give you a good
recommendation. Then ask their permission to use them as references. If they say yes, get their correct title, work address and work phone number. You could also ask them to take the time to write out a general letter of recommendation for future use.
Days before
2. Research the company. Even before applying, learn all you can about this particular organization and the field. The interviewer will expect you to know something about the work you want to be doing, and about the place where you want to be doing it. It also shows you care -- which does count for something.

3. Identify your key skills and accomplishments. Make a list and be ready to describe
your personal and professional strengths, your transferable skills and your relevant accomplishments. With your research, you have been able to identify qualities that the company values. Come up with a few personal anecdotes that illustrate your possession of those qualities.

4. Practice the interview.Practice makes perfect, and it will give you confidence and
a sense of ease when you're truly in the hot seat at an interview.
5. Check clothing. Make sure your suit is clean, shirt ironed, and shoes polished. Now's your chance to check whether your best outfit needs to go to the cleaners or a seamstress for repairs. If you're going to borrow any clothing from a friend or buy a
new pair of shoes, do it ahead of time so that you can be sure everything fits well.

6. Test drive. If you are unsure of the location of the interview, drive there. This way you can be sure of the building, the time to get there and any parking difficulties.Day before
7. Call to reconfirm. when you first make an appointment for an interview that you ask the name of the secretary or receptionist. Then when you call back to reconfirm you can refer to them by name.

8. Prepare clothes. "Check head to toe what you're going to be wearing." Also, gather
all the things you'll be bringing to the interview: an extra copy of your resume,
references, a portfolio, a pad of paper, a pen.

9. Watch the weather. "If the weather's going to be bad, be prepared,"

10.Get a good night's sleep. It's a big day -- you'll want to be fresh and alert.

Day of interview
11.Work it off. Exercising earlier in the day if possible, to get your blood flowing
and to release stress.

12.Get to the interview on time. Arrive 10 minutes early even. No excuses.

13.Last-minute check. Take a look in your car mirror or in a bathroom mirror at a
location near interview. Fix your lipstick, pull loose hairs off the shoulder of
your jacket, make sure your shirt is properly tucked in and straighten your tie.
Now smile.

Waiting
14.Look confident and busy. More than likely you'll end up in a waiting room for at
least a few minutes. Don't get sloppy -- you are already on. When the interviewer
walks in, be ready to shake hands. "Remember, purses and briefcases in left hand.

During
15. Pay attention. After all your preparation, the interview will be a snap, Since
you prepared, it won't be nearly as much of a struggle -- but it is vital that
you listen to the interviewer.

16. Relax. If you're nervous "When you sit, keep your palms up” This lowers your
blood pressure and air dries the palms."

Right after
17. Write it down. On a pad of paper in your car, write down your impressions of the
company and the interview, and the names of your potential co-workers . If you're
called for another interview, you can review what was discussed at the first one,
thus preparing even better for the second

Day after
18. Send thank you note. Thank the interviewer(s) for taking the time to meet with you.
This is a polite gesture -- and a subtle reminder to them of you.

Week after
19. Make follow-up call. If you haven't heard from the company and you are still
interested in the job, make a quick call to the person who interviewed you or
the Human Resources department. See if they are closer to making a decision and
when you might expect to hear from them. Go ahead and tell them how excited you
are about the prospect of working there.

Weeks after
20. Be patient. You might hear about the job right away. More likely, the company
will take some time to interview candidates and then review them. If you got
good vibes from the interview or the follow-up call, just be patient.

But don't quit your job search, just because you found what you think will be your
dream job.It might not work out, and waiting before applying somewhere else is
going to drag out your job search. While some companies won't call or write you
when the job is filled -- which is irritating as hell -- others may just be taking
their time.

A job interview that does not result in a job need not be a failure. You can learn from
the experience, improving your presentation and concentration for the next time.

Regarding Java Sound API

2008-12-30T07:02:00.000-08:00

http://java.sun.com/j2se/1.5.0/docs/guide/sound/programmer_guide/contents.html

General Questions

2008-12-30T04:24:00.000-08:00

Tell me about you!

Keep your answer to one or two minutes; don't ramble. Use your resume summary as a base to start.

What do you know about our company?

Do your homework before the interview! Spend some time online or at the library researching the company. Find out as much as you can, including products, size, income, reputation, image, management talent, people, skills, history and philosophy. Project an informed interest; let the interviewer tell you about the company.

Why do you want to work for us?

Don't talk about what you want; first, talk about their needs: You would like to be part of a specific company project; you would like to solve a company problem; you can make a definite contribution to specific company goals.

What would you do for us? What can you do for us that someone else can't?

Relate past experiences that show you've had success in solving previous employer problem(s) that may be similar to those of the prospective employer.

What about the job offered do you find the most attractive? Least attractive?

List three or more attractive factors and only one minor unattractive factor.

Why should we hire you?

Because of your knowledge, experience, abilities and skills.

What do you look for in a job?

An opportunity to use your skills, to perform and be recognized.

Please give me your definition of a .... (the position for which you are being interviewed).

Keep it brief -- give an actions- and results-oriented definition.

How long would it take you to make a meaningful contribution to our firm?

Not long at all -- you expect only a brief period of adjustment to the learning curve.

How long would you stay with us?

As long as we both feel I'm contributing, achieving, growing, etc.

Strategies for Improving GD Skills

2008-12-30T04:23:00.000-08:00

Observe

Attend as many seminars and tutorials as possible and notice what other students do. Ask yourself:

How do other students make critical comments?

How do they ask questions?

How do they disagree with or support arguments?

What special phrases do they use to show politeness even when they are voicing disagreement?

How do they signal to interrupt, ask a question or make a point?

Practice

Start practicing your discussion skills in an informal setting or with a small group. Start with asking questions of fellow students. Ask them about the course material. Ask for their opinions. Ask for information or ask for help.

Participate
Take every opportunity to take part in social/informal discussions as well as more structured/formal discussion. Start by making small contributions to tutorial discussions; prepare a question to ask, or agree with another speaker's remarks.

Do

Speak pleasantly and politely to the group.

Respect the contribution of every speaker.

Remember that a discussion is not an argument. Learn to disagree politely.

Think about your contribution before you speak. How best can you answer the question/ contribute to the topic?

Try to stick to the discussion topic. Don't introduce irrelevant information.

Be aware of your body language when you are speaking.

Agree with and acknowledge what you find interesting.

Don't

Lose your temper. A discussion is not an argument.

Shout. Use a moderate tone and medium pitch.

Use too many gestures when you speak. Gestures like finger pointing and table thumping can appear aggressive.

Dominate the discussion. Confident speakers should allow quieter students a chance to contribute.

Draw too much on personal experience or anecdote. Although some tutors encourage students to reflect on their own experience, remember not to generalise too much.

Interrupt. Wait for a speaker to finish what they are saying before you speak.

Leading a Discussion

You may be in a seminar group that requires you to lead a group discussion, or lead a discussion after an oral presentation. You can demonstrate leadership by:

introducing yourself and the members of the group

stating the purpose of the discussion

inviting quiet group members to speak

being objective

summarizing the discussion

Chairing a Group Discussion

When chairing a discussion group you must communicate in a positive way to assist the speakers in accomplishing their objective. There are at least four leadership skills you can use to influence other people positively and help your group achieve its purpose. These skills include:

introducing the topic and purpose of the discussion,

making sure all members have approximately the same time, (i.e. no one dominates the discussion by taking too much time)

thanking group members for their contribution

being objective in summarizing the group's discussion and achievements.

Rocking FireFox!!

2008-12-30T04:21:00.001-08:00

Mozilla firefox originally known as "Phoenix" and briefly as "Mozilla
Firebird", is a free, cross-platform, graphical web browser developed
by the Mozilla Foundation. It is a new internet browser in the market
which really brings a competition for internet explorer. It is a good
alternative for internet explorer. The firefox is open source feature
which means that source code for the program is available to anyone
who cares to download it.
The reasons why the firefox browser is getting famous is stated in the
points below.

To Download for Free Visit
www.Firefox . in

Popup Blocking

An internet browser without a popup blocker is like having a broadband
connection without a fireball. Popup blocker is a really good blocking
software which stops ads and never interferes with your browser
navigation. If you want to get rid of the problem of popup ads,
without introducing disturbing side affects, then firefox is the best
site you can choose. Trying this with internet explorer would probably
bring your pc above your head. You can also easily access the list of
websites that the popup blocker blocks, and altering its state by a
simple mouse click.

Download Manager

Download manager allows you to manipulate and take control of your
downloaded files. Mozilla Firefoxâ€™s download manager contains just
the essential to allow you to control your downloads. You can pause
your downloads and continue it later, sometimes which is not possible
with internet explorerâ€™s download manager. The download manager
stores the information such as size and location of your downloaded
file. When the download is complete, a small notification is displayed
in the lower side of the screen.

Tab Browsing

Sometimes too many windows open at a time can be a bit annoying, which
can also be said as time consuming, firefox features tab browsing. Tab
Browsing changes the way you use the internet by allowing you to open
links on a page in background â€œTabsâ€ and then read them when
youâ€™re ready. No confusing new windows, no need for context menus,
just hold down Ctrl when clicking a link, or use your middle mouse
button.

Integrated Search Engine

The internet explorer programmers didnâ€™t think of this? Mozilla
Firefox have launched in with the search engine. The default search
engine is Google, of course, with the ability to access others. The
search takes a very small space, which is a plus point compared to
internet explorer.

Options

The Mozilla firefox is less confusing and less disturbing than the
internet explorer. With Mozillaâ€™s firefox you can easily find the
way through each site. The â€œDownloadsâ€ option allows you to
choose, which program will automatically open a downloaded file is
made.
Page Info When you right click on a page, and select â€œpage infoâ€
the window will start displaying huge amount of information for the
webpage you need. General information as well as a Link tab showing
all the links that the page contains are also listed in the site.

Faster Response

On Mozilla Firefox it is typically faster to load a webpage than on
the internet explorer.

Keeps HTML Formatting

While you are copying from a webpage to a file the Mozilla Firefox is
able to restore the html format. For example, when copying html
formatted text from a webpage and pasting it on a note pad, the text
through Mozilla Firefox keeps the format of text and the html format,
where the internet explorer doesnâ€™t.

Open Source Advantage

The Mozilla Firefox is a open source project where many of the
independent programmers can work on finding security.

Smaller Download

Downloading a Mozilla Firefox programmer is very smaller and quicker,
which is compared to as half the size of internet explorer.

Block Images

The pictures on the webpage can be disturbing and so the Mozilla
Firefox gives an option of blocking the images form the webpage. This
feature can be of use when you are handing a site that holds many
pictures, and many ads, which can be a problem for faster surfing.
Internet explorer does not provide this facility.

Mozilla Firefox is an alternate browser to internet explorer. Firefox
has defiantly broken ground in the war of the browsers. I know there
are many out there who would think otherwise and never settle for any
browser other than internet explorer.

Forward this mail to all fo your friends....

EJB sample questions with multiple choices

2008-12-30T04:18:00.000-08:00

1.What does CTM stands for

a)CORBA transaction monitor.

b)Component transaction monitor.

c)Component task monitor.

2. javax.ejb.EJBObject extends

a)javax.ejb.EJBHome

b)javax.ejb.SessionBean

c)javax.ejb.Remote

d)java.rmi.Remote

3. Bean's business methods are implemented by

a)javax.ejb.EJBHome

b)javax.ejb.EJBObject

c)javax.ejb.EntityBean

4. All EJB remote interface types types extend

a)javax.ejb.EJBHome

b)javax.ejb.SessionBean

c)javax.ejb.EJBObject

5. The life-cycle methods of a server-side bean are defined by

a)javax.ejb.EJBObject

b)javax.ejb.EJBHome

c)javax.ejb.EntityBean

6. Session beans don’t have

a)ejbCreate() method

b)ejbStore() method

c)ejbRemove() method

7 EntityDescriptor extends

a)SessionDescriptor

b)ControlDescriptor

c)DeploymentDescriptor

8 After an entity bean is instantiated and placed in the pool, it is given reference to a -----------------------

a)javax.ejb.EJBHome

b)javax.ejb.EJBObject

c)javax.ejb.EJBContext

9 State of Entity Bean instances is persisted directly into

a)secondary storage

b)database

10 A stateful session bean is

a)shared among multiple clients

b)not shared among multiple clients

11 Entity beans are

a)shared components

b)non-shared components

12 EJB by default -------------- concurrent access to bean instances.

a)allows

b)prohibits

13 EJB specification -------------- synchronized key words.

a)prohibits

b)allows

14 JRMP lacks inherent support for ------------ and ------------------- services that is part of the

CORBAIIOP specification.

15 When a bean instance is in the --------- state, it can accept client requests.

a)Ready

b)Pooled

c)Does not exist

Advanced EJB interview questions

2008-12-30T04:17:00.002-08:00

1. Are enterprise beans allowed to use Thread.sleep()? -
Enterprise beans make use of the services provided by the EJB container, such as life-cycle management. To avoid conflicts with these services, enterprise beans are restricted from performing certain operations: Managing or synchronizing threads
2. Is it possible to write two EJB’s that share the same Remote and Home interfaces, and have different bean classes? if so, what are the advantages/disadvantages? - It’s certainly possible. In fact, there’s an example that ships with the Inprise Application Server of an Account interface with separate implementations for CheckingAccount and SavingsAccount, one of which was CMP and one of which was BMP.

3. Is it possible to specify multiple JNDI names when deploying an EJB? - No. To achieve this you have to deploy your EJB multiple times each specifying a different JNDI name.
4. Is there any way to force an Entity Bean to store itself to the db? I don’t wanna wait for the container to update the db, I want to do it NOW! Is it possible? - Specify the transaction attribute of the bean as RequiresNew. Then as per section 11.6.2.4 of the EJB v 1.1 spec EJB container automatically starts a new transaction before the method call. The container also performs the commit protocol before the method result is sent to the client.
5. I am developing a BMP Entity bean. I have noticed that whenever the create method is invoked, the ejbLoad() and the ejbStore() methods are also invoked. I feel that once my database insert is done, having to do a select and update SQL queries is major overhead. is this behavior typical of all EJB containers? Is there any way to suppress these invocations? - This is the default behaviour for EJB. The specification states that ejbLoad() will be called before every transaction and ejbStore() after every transaction. Each Vendor has optimizations, which are proprietary for this scenario.
6. Can an EJB send asynchronous notifications to its clients? - Asynchronous notification is a known hole in the first versions of the EJB spec. The recommended solution to this is to use JMS, which is becoming available in J2EE-compliant servers. The other option, of course, is to use client-side threads and polling. This is not an ideal solution, but it’s workable for many scenarios.
7. How can I access EJB from ASP? - You can use the Java 2 Platform, Enterprise Edition Client Access Services (J2EETM CAS) COM Bridge 1.0, currently downloadable from Sun
8. Is there a guarantee of uniqueness for entity beans? - There is no such guarantee. The server (or servers) can instantiate as many instances of the same underlying Entity Bean (with the same PK) as it wants. However, each instance is guaranteed to have up-to-date data values, and be transactionally consistent, so uniqueness is not required. This allows the server to scale the system to support multiple threads, multiple concurrent requests, and multiple hosts.
9. How do the six transaction attributes map to isolation levels like “dirty read”? Will an attribute like “Required” lock out other readers until I’m finished updating? - The Transaction Attributes in EJB do not map to the Transaction Isolation levels used in JDBC. This is a common misconception. Transaction Attributes specify to the container when a Transaction should be started, suspended(paused) and committed between method invocations on Enterprise JavaBeans. For more details and a summary of Transaction Attributes refer to section 11.6 of the EJB 1.1 specification.
10. I have created a remote reference to an EJB in FirstServlet. Can I put the reference in a servlet session and use that in SecondServlet? - Yes. The EJB client (in this case your servlet) acquires a remote reference to an EJB from the Home Interface; that reference is serializable and can be passed from servlet to servlet. If it is a session bean, then the EJB server will consider your web client’s servlet session to correspond to a single EJB session, which is usually (but not always) what you want.
11. Can the primary key in the entity bean be a Java primitive type such as int? - The primary key can’t be a primitive type–use the primitive wrapper classes, instead. For example, you can use java.lang.Integer as the primary key class, but not int (it has to be a class, not a primitive)
12. What’s new in the EJB 2.0 specification? - Following are the main features supported in EJB 2.0: Integration of EJB with JMS, Message Driven Beans, Implement additional Business methods in Home interface which are not specific for bean instance, EJB QL.

13. How many types of protocol implementations does RMI have? - RMI has at least three protocol implementations: Java Remote Method Protocol(JRMP), Internet Inter ORB Protocol(IIOP), and Jini Extensible Remote Invocation(JERI). These are alternatives, not part of the same thing, All three are indeed layer 6 protocols for those who are still speaking OSI reference model.

14. What is the need of Remote and Home interfaces. Why can’t there be one? - In a few words, I would say that the main reason is because there is a clear division of roles and responsabilities between the two interfaces. The home interface is your way to communicate with the container, that is who is responsable of creating, locating even removing one or more beans. The remote interface is your link to the bean, that will allow you to remotely access to all its methods and members. As you can see there are two distinct elements (the container and the beans) and you need two different interfaces for accessing to both of them.

15. What is the difference between Java Beans and EJB? - Java Beans are client-side objects and EJBs are server side object, and they have completely different development, lifecycle, purpose.

16. Question With regard to Entity Beans, what happens if both my EJB Server and Database crash, what will happen to unsaved changes? Is there any transactional log file used? - Actually, if your EJB server crashes, you will not even be able to make a connection to the server to perform a bean lookup, as the server will no longer be listening on the port for incoming JNDI lookup requests. You will lose any data that wasn’t committed prior to the crash. This is where you should start looking into clustering your EJB server. Any unsaved and uncommited changes are lost the moment your EJB Server crashes. If your database also crashes, then all the saved changes are also lost unless you have some backup or some recovery mechanism to retrieve the data. So consider database replication and EJB Clustering for such scenarios, though the occurence of such a thing is very very rare. Thx, Uma All databse have the concept of log files(for exampe oracle have redo log files concept). So if data bases crashes then on starting up they fill look up the log files to perform all pending jobs. But is EJB crashes, It depend upon the container how frequenlty it passivates or how frequesntly it refreshes the data with Database.

17. Question Can you control when passivation occurs? - The developer, according to the specification, cannot directly control when passivation occurs. Although for Stateful Session Beans, the container cannot passivate an instance that is inside a transaction. So using transactions can be a a strategy to control passivation. The ejbPassivate() method is called during passivation, so the developer has control over what to do during this exercise and can implement the require optimized logic. Some EJB containers, such as BEA WebLogic, provide the ability to tune the container to minimize passivation calls. Taken from the WebLogic 6.0 DTD - “The passivation-strategy can be either “default” or “transaction”. With the default setting the container will attempt to keep a working set of beans in the cache. With the “transaction” setting, the container will passivate the bean after every transaction (or method call for a non-transactional invocation).”

18. Does RMI-IIOP support dynamic downloading of classes? - No, RMI-IIOP doesn’t support dynamic downloading of the classes as it is done with CORBA in DII (Dynamic Interface Invocation).Actually RMI-IIOP combines the usability of Java Remote Method Invocation (RMI) with the interoperability of the Internet Inter-ORB Protocol (IIOP).So in order to attain this interoperability between RMI and CORBA,some of the features that are supported by RMI but not CORBA and vice versa are eliminated from the RMI-IIOP specification.
19. Does EJB 1.1 support mandate the support for RMI-IIOP ? What is the meaning of “the client API must support the Java RMI-IIOP programming model for portability, but the underlying protocol can be anything” ? - EJB1.1 does mandate the support of RMI-IIOP. There are 2 types of implementations that an EJB Server might provide: CORBA-based EJB Servers and Proprietry EJB Servers. Both support the RMI-IIOP API but how that API is implemented is a different story. (NB: By API we mean the interface provided to the client by the stub or proxy). A CORBA-based EJB Server actually implements its EJB Objects as CORBA Objects (it therefore encorporates an ORB and this means that EJB’s can be contacted by CORBA clients (as well as RMI-IIOP clients) A proprietry EJB still implements the RMI-IIOP API (in the client’s stub) but the underlying protocol can be anything. Therefore your EJB’s CANNOT be contacted by CORBA clients. The difference is that in both cases, your clients see the same API (hence, your client portability) BUT how the stubs communicate with the server is different.

20. The EJB specification says that we cannot use Bean Managed Transaction in Entity Beans. Why? - The short, practical answer is… because it makes your entity beans useless as a reusable component. Also, transaction management is best left to the application server - that’s what they’re there for. It’s all about atomic operations on your data. If an operation updates more than one entity then you want the whole thing to succeed or the whole thing to fail, nothing in between. If you put commits in the entity beans then it’s very difficult to rollback if an error occurs at some point late in the operation.
21. Can I invoke Runtime.gc() in an EJB? - You shouldn’t. What will happen depends on the implementation, but the call will most likely be ignored. You should leave system level management like garbage collection for the container to deal with. After all, that’s part of the benefit of using EJBs, you don’t have to manage resources yourself.

22. What is clustering? What are the different algorithms used for clustering? - Clustering is grouping machines together to transparantly provide enterprise services.The client does not now the difference between approaching one server or approaching a cluster of servers.Clusters provide two benefits: scalability and high availability. Further information can be found in the JavaWorld article J2EE Clustering.

23. What is the advantage of using Entity bean for database operations, over directly using JDBC API to do database operations? When would I use one over the other? - Entity Beans actually represents the data in a database. It is not that Entity Beans replaces JDBC API. There are two types of Entity Beans Container Managed and Bean Mananged. In Container Managed Entity Bean - Whenever the instance of the bean is created the container automatically retrieves the data from the DB/Persistance storage and assigns to the object variables in bean for user to manipulate or use them. For this the developer needs to map the fields in the database to the variables in deployment descriptor files (which varies for each vendor). In the Bean Managed Entity Bean - The developer has to specifically make connection, retrive values, assign them to the objects in the ejbLoad() which will be called by the container when it instatiates a bean object. Similarly in the ejbStore() the container saves the object values back the the persistance storage. ejbLoad and ejbStore are callback methods and can be only invoked by the container. Apart from this, when you use Entity beans you dont need to worry about database transaction handling, database connection pooling etc. which are taken care by the ejb container. But in case of JDBC you have to explicitly do the above features. what suresh told is exactly perfect. ofcourse, this comes under the database transations, but i want to add this. the great thing about the entity beans of container managed, whenever the connection is failed during the transaction processing, the database consistancy is mantained automatically. the container writes the data stored at persistant storage of the entity beans to the database again to provide the database consistancy. where as in jdbc api, we, developers has to do manually.

24. What is the role of serialization in EJB? - A big part of EJB is that it is a framework for underlying RMI: remote method invocation. You’re invoking methods remotely from JVM space ‘A’ on objects which are in JVM space ‘B’ — possibly running on another machine on the network. To make this happen, all arguments of each method call must have their current state plucked out of JVM ‘A’ memory, flattened into a byte stream which can be sent over a TCP/IP network connection, and then deserialized for reincarnation on the other end in JVM ‘B’ where the actual method call takes place. If the method has a return value, it is serialized up for streaming back to JVM A. Thus the requirement that all EJB methods arguments and return values must be serializable. The easiest way to do this is to make sure all your classes implement java.io.Serializable.
25. What is EJB QL? - EJB QL is a Query Language provided for navigation across a network of enterprise beans and dependent objects defined by means of container managed persistence. EJB QL is introduced in the EJB 2.0 specification. The EJB QL query language defines finder methods for entity beans with container managed persistenceand is portable across containers and persistence managers. EJB QL is used for queries of two types of finder methods: Finder methods that are defined in the home interface of an entity bean and which return entity objects. Select methods, which are not exposed to the client, but which are used by the Bean Provider to select persistent values that are maintained by the Persistence Manager or to select entity objects that are related to the entity bean on which the query is defined.

Database- Frequently Asked Questions

2008-12-30T04:17:00.001-08:00

1.) Explain Various Normalization Forms?

The Normal Forms Are As Follows…

First normal form (1NF) sets the basic rules for an organized database:

* Eliminate duplicative columns from the same database table.
* Create separate tables for each group of related data and identify each row with a unique column or set of columns (the primary key).

Second normal form (2NF) further Handles the concept of removing duplicative data:

* Meet all the requirements of the first normal form.
* Remove subsets of data that apply to multiple rows of a table and place them in separate tables.
* Create relationships between these new tables and their predecessors through the use of foreign keys.

Third normal form (3NF) goes one large step further:

* Meet all the requirements of the second normal form.
* Remove columns that are not dependent upon the primary key.

Finally, fourth normal form (4NF) has one additional requirement:

* Meet all the requirements of the third normal form.
* A relation is in 4NF if it has no multi-valued dependencies

2.) What is the difference between delete,drop and truncate?

The delete statement will result in the table spaces or memories would remain as the current size and table structureremain in the database. Delete is not effective when you use it to remove all data from a table, because it takes up storeage spaces due to unclear memories. The truncate statement will result in clearing table spaces or memories and the table structure remain in the database. Therefore it free table storage spaces and only use it when you need to remove all data from a table. The drop statement will result in completely removing the table from the database. Note: Statements above are made with the assumption that a commit is has been executed. Once a commit statement is executed (commit is final). Therefore, rollback a transaction will not work if commit statement is executed.

3.) Which view shows all partitions of a table and their tablespaces?

user_tab_partitions,all_tab_partitions,dba_tab_partitions

4.) What is a value set?

A set of permitted values for the given attribute. eg GRADE attribute in STUDENT table can have only values like A, B,C, D only.

5.) Difference between user and end-user?

The final or ultimate user of a computer system. The end user is the individual who uses the product after it has been fully developed and marketed. The term is useful because it distinguishes two classes of users, users who require a bug -free and finished product (end users), and users who may use the same product for development purposes. The term end user usually implies an individual with a relatively low level of computer expertise. Unless you are a programmer or engineer, you are almost certainly an end user. An individual who uses a computer. This includes expert programmers as well as novices. An end user is any individual who runs an application program.

6.) Briefly explain the difference between first, second, third and fourth normal forms?

1NF: A table is set to be in first NF if we identify the functional dependency. 2NF: A table is set to be in first NF if we identify and delete partial functional dependency. 3NF: A table is set to be in 3rd NF when we identify and delete transitive dependency. Functional dependency: identify a non key attribute which is depends on key attribute. Partial functional dependency: identify an attribute which is partially depends on key attribute. Transitive: identify an key attribute which is independent itself.

7.) What is ER Diagram?

The Entity-Relationship (ER) model was originally proposed by Peter in 1976 [Chen76] as a way to unify the network and relational database views. Simply stated the ER model is a conceptual data model that views the real world as entities and relationships. A basic component of the model is the Entity-Relationship diagram which is used to visually represents data objects.Since Chen wrote his paper the model has been extended and today it is commonly used for database design For the databasedesigner, the utility of the ER model is: it maps well to the relational model. The constructs used in the ER model can easily be transformed into relational tables. it is simple and easy to understand with a minimum of training. Therefore, the model can be used by the database designer to communicate the design to the end user. In addition, the model can be used as a design plan by the database developer to implement a data model in a specific database management software

C Interview Questions and Answers

2008-12-30T04:16:00.000-08:00

Question : What is C language?

Answers : The C programming language is a standardized programming language developed in the early 1970s by Ken Thompson and Dennis Ritchie for use on the UNIX operating system. It has since spread to many other operating systems, and is one of the most widely used programming languages. C is prized for its efficiency, and is the most popular programming language for writing system software, though it is also used for writing applications. ...

printf() Function
What is the output of printf("%d")?

1. When we write printf("%d",x); this means compiler will print the value of x. But as here, there is nothing after �%d� so compiler will show in output window garbage value.

2. When we use %d the compiler internally uses it to access the argument in the stack (argument stack). Ideally compiler determines the offset of the data variable depending on the format specification string. Now when we write printf("%d",a) then compiler first accesses the top most element in the argument stack of the printf which is %d and depending on the format string it calculated to offset to the actual data variable in the memory which is to be printed. Now when only %d will be present in the printf then compiler will calculate the correct offset (which will be the offset to access the integer variable) but as the actual data object is to be printed is not present at that memory location so it will print what ever will be the contents of that memory location.

3. Some compilers check the format string and will generate an error without the proper number and type of arguments for things like printf(...) and scanf(...).

malloc() Function- What is the difference between "calloc(...)" and "malloc(...)"?

1. calloc(...) allocates a block of memory for an array of elements of a certain size. By default the block is initialized to 0. The total number of memory allocated will be (number_of_elements * size).

malloc(...) takes in only a single argument which is the memory required in bytes. malloc(...) allocated bytes of memory and not blocks of memory like calloc(...).

2. malloc(...) allocates memory blocks and returns a void pointer to the allocated space, or NULL if there is insufficient memory available.

calloc(...) allocates an array in memory with elements initialized to 0 and returns a pointer to the allocated space. calloc(...) calls malloc(...) in order to use the C++ _set_new_mode function to set the new handler mode.

printf() Function- What is the difference between "printf(...)" and "sprintf(...)"?
sprintf(...) writes data to the character array whereas printf(...) writes data to the standard output device.

Compilation How to reduce a final size of executable?

Size of the final executable can be reduced using dynamic linking for libraries.

Linked Lists -- Can you tell me how to check whether a linked list is circular?

Create two pointers, and set both to the start of the list. Update each as follows:

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while (pointer1) {
pointer1 = pointer1->next;
pointer2 = pointer2->next;
if (pointer2) pointer2=pointer2->next;
if (pointer1 == pointer2) {
print ("circular");
}
}

If a list is circular, at some point pointer2 will wrap around and be either at the item just before pointer1, or the item before that. Either way, its either 1 or 2 jumps until they meet.

"union" Data Type What is the output of the following program? Why?

#include
main() {
typedef union {
int a;
char b[10];
float c;
}
Union;

Union x,y = {100};
x.a = 50;
strcpy(x.b,"hello");
x.c = 21.50;
printf("Union x : %d %s %f n",x.a,x.b,x.c);
printf("Union y : %d %s %f n",y.a,y.b,y.c);
}

String Processing --- Write out a function that prints out all the permutations of a string. For example, abc would give you abc, acb, bac, bca, cab, cba.
void PrintPermu (char *sBegin, char* sRest) {
int iLoop;
char cTmp;
char cFLetter[1];
char *sNewBegin;
char *sCur;
int iLen;
static int iCount;

iLen = strlen(sRest);
if (iLen == 2) {
iCount++;
printf("%d: %s%s\n",iCount,sBegin,sRest);
iCount++;
printf("%d: %s%c%c\n",iCount,sBegin,sRest[1],sRest[0]);
return;
} else if (iLen == 1) {
iCount++;
printf("%d: %s%s\n", iCount, sBegin, sRest);
return;
} else {
// swap the first character of sRest with each of
// the remaining chars recursively call debug print
sCur = (char*)malloc(iLen);
sNewBegin = (char*)malloc(iLen);
for (iLoop = 0; iLoop < iLen; iLoop ++) {
strcpy(sCur, sRest);
strcpy(sNewBegin, sBegin);
cTmp = sCur[iLoop];
sCur[iLoop] = sCur[0];
sCur[0] = cTmp;
sprintf(cFLetter, "%c", sCur[0]);
strcat(sNewBegin, cFLetter);
debugprint(sNewBegin, sCur+1);
}
}
}

void main() {
char s[255];
char sIn[255];
printf("\nEnter a string:");
scanf("%s%*c",sIn);
memset(s,0,255);
PrintPermu(s, sIn);
}

Core Java Interview Questions

2008-12-30T04:15:00.000-08:00

1.what is a transient variable?
A transient variable is a variable that may not be serialized.

2.which containers use a border Layout as their default layout?
The window, Frame and Dialog classes use a border layout as their default layout.

3.Why do threads block on I/O?
Threads block on i/o (that is enters the waiting state) so that other threads may execute while the i/o Operation is performed.

4. How are Observer and Observable used?
Objects that subclass the Observable class maintain a list of observers. When an Observable object is updated it invokes the update() method of each of its observers to notify the observers that it has changed state. The Observer interface is implemented by objects that observe Observable objects.

5. What is synchronization and why is it important?
With respect to multithreading, synchronization is the capability to control the access of multiple threads to shared resources. Without synchronization, it is possible for one thread to modify a shared object while another thread is in the process of using or updating that object's value. This often leads to significant errors.

6. Can a lock be acquired on a class?
Yes, a lock can be acquired on a class. This lock is acquired on the class's Class object..

7. What's new with the stop(), suspend() and resume() methods in JDK 1.2?
The stop(), suspend() and resume() methods have been deprecated in JDK 1.2.

8. Is null a keyword?
The null value is not a keyword.

9. What is the preferred size of a component?
The preferred size of a component is the minimum component size that will allow the component to display normally.

10. What method is used to specify a container's layout?
The setLayout() method is used to specify a container's layout.

11. Which containers use a FlowLayout as their default layout?
The Panel and Applet classes use the FlowLayout as their default layout.

12. What state does a thread enter when it terminates its processing?
When a thread terminates its processing, it enters the dead state.

13. What is the Collections API?
The Collections API is a set of classes and interfaces that support operations on collections of objects.

14. Which characters may be used as the second character of an identifier,
but not as the first character of an identifier?
The digits 0 through 9 may not be used as the first character of an identifier but they may be used after the first character of an identifier.

15. What is the List interface?
The List interface provides support for ordered collections of objects.

16. How does Java handle integer overflows and underflows?
It uses those low order bytes of the result that can fit into the size of the type allowed by the operation.

17. What is the Vector class?
The Vector class provides the capability to implement a growable array of objects

18. What modifiers may be used with an inner class that is a member of an outer class?
A (non-local) inner class may be declared as public, protected, private, static, final, or abstract.

19. What is an Iterator interface?
The Iterator interface is used to step through the elements of a Collection.

20. What is the difference between the >> and >>> operators?
The >> operator carries the sign bit when shifting right. The >>> zero-fills bits that have been shifted out.

21. Which method of the Component class is used to set the position and
size of a component?
setBounds()

22. How many bits are used to represent Unicode, ASCII, UTF-16, and UTF-8 characters?
Unicode requires 16 bits and ASCII require 7 bits. Although the ASCII character set uses only 7 bits, it is usually represented as 8 bits. UTF-8 represents characters using 8, 16, and 18 bit patterns. UTF-16 uses 16-bit and larger bit patterns.

23What is the difference between yielding and sleeping?
When a task invokes its yield() method, it returns to the ready state. When a task invokes its sleep() method, it returns to the waiting state.

24. Which java.util classes and interfaces support event handling?
The EventObject class and the EventListener interface support event processing.

25. Is sizeof a keyword?
The sizeof operator is not a keyword.

26. What are wrapped classes?
Wrapped classes are classes that allow primitive types to be accessed as objects.

27. Does garbage collection guarantee that a program will not run out of memory?
Garbage collection does not guarantee that a program will not run out of memory. It is possible for programs to use up memory resources faster than they are garbage collected. It is also possible for programs to create objects that are not subject to garbage collection

28. What restrictions are placed on the location of a package statement
within a source code file?
A package statement must appear as the first line in a source code file (excluding blank lines and comments).

29. Can an object's finalize() method be invoked while it is reachable?
An object's finalize() method cannot be invoked by the garbage collector while the object is still reachable. However, an object's finalize() method may be invoked by other objects.

30. What is the immediate superclass of the Applet class?
Panel

31. What is the difference between preemptive scheduling and time slicing?
Under preemptive scheduling, the highest priority task executes until it enters the waiting or dead states or a higher priority task comes into existence. Under time slicing, a task executes for a predefined slice of time and then reenters the pool of ready tasks. The scheduler then determines which task should execute next, based on priority and
other factors.

32. Name three Component subclasses that support painting.
The Canvas, Frame, Panel, and Applet classes support painting.

33. What value does readLine() return when it has reached the end of a file?
The readLine() method returns null when it has reached the end of a file.

34. What is the immediate superclass of the Dialog class?
Window
35. What is clipping?
Clipping is the process of confining paint operations to a limited area or shape.

36. What is a native method?
A native method is a method that is implemented in a language other than Java.

37. Can a for statement loop indefinitely?
Yes, a for statement can loop indefinitely. For example, consider the following:
for(;;) ;

38. What are order of precedence and associativity, and how are they used?
Order of precedence determines the order in which operators are evaluated in expressions. Associatity determines whether an expression is evaluated left-to-right or right-to-left

39. When a thread blocks on I/O, what state does it enter?
A thread enters the waiting state when it blocks on I/O.

40. To what value is a variable of the String type automatically initialized?
The default value of an String type is null.

41. What is the catch or declare rule for method declarations?
If a checked exception may be thrown within the body of a method, the method must either catch the exception or declare it in its throws clause.

42. What is the difference between a MenuItem and a CheckboxMenuItem?
The CheckboxMenuItem class extends the MenuItem class to support a menu item that may be checked or unchecked.

43. What is a task's priority and how is it used in scheduling?
A task's priority is an integer value that identifies the relative order in which it should be executed with respect to other tasks. The scheduler attempts to schedule higher priority tasks before lower priority tasks.

44. What class is the top of the AWT event hierarchy?
The java.awt.AWTEvent class is the highest-level class in the AWT event-class hierarchy.

45. When a thread is created and started, what is its initial state?
A thread is in the ready state after it has been created and started.

46. Can an anonymous class be declared as implementing an interface and extending a class?
An anonymous class may implement an interface or extend a superclass, but may not be declared to do both.

47. What is the range of the short type?
The range of the short type is -(2^15) to 2^15 - 1.

48. What is the range of the char type?
The range of the char type is 0 to 2^16 - 1.

49. In which package are most of the AWT events that support the event-delegation
model defined?
Most of the AWT-related events of the event-delegation model are defined in the java.awt.event package. The AWTEvent class is defined in the java.awt package.

50. What is the immediate superclass of Menu?
MenuItem

51. What is the purpose of finalization?
The purpose of finalization is to give an unreachable object the opportunity to perform any cleanup processing before the object is garbage collected.

52. Which class is the immediate superclass of the MenuComponent class.
Object

53. What invokes a thread's run() method?
After a thread is started, via its start() method or that of the Thread class, the JVM invokes the thread's run() method when the thread is initially executed.

54. What is the difference between the Boolean & operator and the && operator?
If an expression involving the Boolean & operator is evaluated, both operands are evaluated. Then the & operator is applied to the operand. When an expression involving the && operator is evaluated, the first operand is evaluated. If the first operand returns a value of true then the second operand is evaluated. The && operator is then applied to the first and second operands. If the first operand evaluates to false, the evaluation of the second operand is skipped.

55. Name three subclasses of the Component class.
Box.Filler, Button, Canvas, Checkbox, Choice, Container, Label, List, Scrollbar, or TextComponent

56. What is the GregorianCalendar class?
The GregorianCalendar provides support for traditional Western calendars.

57. Which Container method is used to cause a container to be laid out and redisplayed?
validate()

8. What is the purpose of the Runtime class?
The purpose of the Runtime class is to provide access to the Java runtime system.

59. How many times may an object's finalize() method be invoked by the
garbage collector?
An object's finalize() method may only be invoked once by the garbage collector.

60. What is the purpose of the finally clause of a try-catch-finally statement?
The finally clause is used to provide the capability to execute code no matter whether or not an exception is thrown or caught.

61. What is the argument type of a program's main() method?
A program's main() method takes an argument of the String[] type.

62. Which Java operator is right associative?
The = operator is right associative.

63. What is the Locale class?
The Locale class is used to tailor program output to the conventions of a particular geographic, political, or cultural region.

64. Can a double value be cast to a byte?
Yes, a double value can be cast to a byte.

65. What is the difference between a break statement and a continue statement?
A break statement results in the termination of the statement to which it applies (switch, for, do, or while). A continue statement is used to end the current loop iteration and return control to the loop statement.

66. What must a class do to implement an interface?
It must provide all of the methods in the interface and identify the interface in its implements clause.

67. What method is invoked to cause an object to begin executing as a separate thread?
The start() method of the Thread class is invoked to cause an object to begin executing as a separate thread.

68. Name two subclasses of the TextComponent class.
TextField and TextArea

69. What is the advantage of the event-delegation model over the earlier event-inheritance model?
The event-delegation model has two advantages over the event-inheritance model. First, it enables event handling to be handled by objects other than the ones that generate the events (or their containers). This allows a clean separation between a component's design and its use. The other advantage of the event-delegation model is that it performs much better in applications where many events are generated. This performance improvement is due to the fact that the event-delegation model does not have to repeatedly process unhandled events, as is the case of the event-inheritance model.

70. Which containers may have a MenuBar?
Frame

71. How are commas used in the intialization and iteration parts of a for statement?
Commas are used to separate multiple statements within the initialization and iteration parts of a for statement.

72. What is the purpose of the wait(), notify(), and notifyAll() methods?
The wait(),notify(), and notifyAll() methods are used to provide an efficient way for threads to wait for a shared resource. When a thread executes an object's wait() method, it enters the waiting state. It only enters the ready state after another thread invokes the object's notify() or notifyAll() methods..

73. What is an abstract method?
An abstract method is a method whose implementation is deferred to a subclass.

74. How are Java source code files named?
A Java source code file takes the name of a public class or interface that is defined within the file. A source code file may contain at most one public class or interface. If a public class or interface is defined within a source code file, then the source code file must take the name of the public class or interface. If no public class or interface is defined within a source code file, then the file must take on a name that is different than its classes and interfaces. Source code files use the .java extension.

75. What is the relationship between the Canvas class and the Graphics class?
A Canvas object provides access to a Graphics object via its paint() method.

76. What are the high-level thread states?
The high-level thread states are ready, running, waiting, and dead.

77. What value does read() return when it has reached the end of a file?
The read() method returns -1 when it has reached the end of a file.

78. Can a Byte object be cast to a double value?
No, an object cannot be cast to a primitive value.

79. What is the difference between a static and a non-static inner class?
A non-static inner class may have object instances that are associated with instances of the class's outer class. A static inner class does not have any object instances.
80. What is the difference between the String and StringBuffer classes?
String objects are constants. StringBuffer objects are not.

81. If a variable is declared as private, where may the variable be accessed?
A private variable may only be accessed within the class in which it is declared.

82. What is an object's lock and which object's have locks?
An object's lock is a mechanism that is used by multiple threads to obtain synchronized access to the object. A thread may execute a synchronized method of an object only after it has acquired the object's lock. All objects and classes have locks. A class's lock is acquired on the class's Class object.

83. What is the Dictionary class?
The Dictionary class provides the capability to store key-value pairs.

84. How are the elements of a BorderLayout organized?
The elements of a BorderLayout are organized at the borders (North, South, East, and West) and the center of a container.

85. What is the % operator?
It is referred to as the modulo or remainder operator. It returns the remainder of dividing the first operand by the second operand.

86. When can an object reference be cast to an interface reference?
An object reference be cast to an interface reference when the object implements the referenced interface.

87. What is the difference between a Window and a Frame?
The Frame class extends Window to define a main application window that can have a menu bar.

88. Which class is extended by all other classes?
The Object class is extended by all other classes.

89. Can an object be garbage collected while it is still reachable?
A reachable object cannot be garbage collected. Only unreachable objects may be garbage collected..

90. Is the ternary operator written x : y ? z or x ? y : z ?
It is written x ? y : z.

91. What is the difference between the Font and FontMetrics classes?
The FontMetrics class is used to define implementation-specific properties, such as ascent and descent, of a Font object.
92. How is rounding performed under integer division?
The fractional part of the result is truncated. This is known as rounding toward zero.

93. What happens when a thread cannot acquire a lock on an object?
If a thread attempts to execute a synchronized method or synchronized statement and is unable to acquire an object's lock, it enters the waiting state until the lock becomes available.

94. What is the difference between the Reader/Writer class hierarchy and the
InputStream/OutputStream class hierarchy?
The Reader/Writer class hierarchy is character-oriented, and the InputStream/OutputStream class hierarchy is byte-oriented.

95. What classes of exceptions may be caught by a catch clause?
A catch clause can catch any exception that may be assigned to the Throwable type. This includes the Error and Exception types.

96. If a class is declared without any access modifiers, where may the class be accessed?
A class that is declared without any access modifiers is said to have package access. This means that the class can only be accessed by other classes and interfaces that are defined within the same package.

97. What is the SimpleTimeZone class?
The SimpleTimeZone class provides support for a Gregorian calendar.

98. What is the Map interface?
The Map interface replaces the JDK 1.1 Dictionary class and is used associate keys with values.

99. Does a class inherit the constructors of its superclass?
A class does not inherit constructors from any of its superclasses.

100. For which statements does it make sense to use a label?
The only statements for which it makes sense to use a label are those statements that can enclose a break or continue statement.

101. What is the purpose of the System class?
The purpose of the System class is to provide access to system resources.

102. Which TextComponent method is used to set a TextComponent to the read-only state?
setEditable()
103. How are the elements of a CardLayout organized?
The elements of a CardLayout are stacked, one on top of the other, like a deck of cards.

104. Is &&= a valid Java operator?
No, it is not.

105. Name the eight primitive Java types.
The eight primitive types are byte, char, short, int, long, float, double, and boolean.

106. Which class should you use to obtain design information about an object?
The Class class is used to obtain information about an object's design.

107. What is the relationship between clipping and repainting?
When a window is repainted by the AWT painting thread, it sets the clipping regions to the area of the window that requires repainting.

108. Is "abc" a primitive value?
The String literal "abc" is not a primitive value. It is a String object.

109. What is the relationship between an event-listener interface and an
event-adapter class?
An event-listener interface defines the methods that must be implemented by an event handler for a particular kind of event. An event adapter provides a default implementation of an event-listener interface.

110. What restrictions are placed on the values of each case of a switch statement?
During compilation, the values of each case of a switch statement must evaluate to a value that can be promoted to an int value.

111. What modifiers may be used with an interface declaration?
An interface may be declared as public or abstract.

112. Is a class a subclass of itself?
A class is a subclass of itself.

113. What is the highest-level event class of the event-delegation model?
The java.util.EventObject class is the highest-level class in the event-delegation class hierarchy.

114. What event results from the clicking of a button?
The ActionEvent event is generated as the result of the clicking of a button.

115. How can a GUI component handle its own events?
A component can handle its own events by implementing the required event-listener interface and adding itself as its own event listener.
116. What is the difference between a while statement and a do statement?
A while statement checks at the beginning of a loop to see whether the next loop iteration should occur. A do statement checks at the end of a loop to see whether the next iteration of a loop should occur. The do statement will always execute the body of a loop at least once.

117. How are the elements of a GridBagLayout organized?
The elements of a GridBagLayout are organized according to a grid. However, the elements are of different sizes and may occupy more than one row or column of the grid. In addition, the rows and columns may have different sizes.

118. What advantage do Java's layout managers provide over traditional windowing systems?
Java uses layout managers to lay out components in a consistent manner across all windowing platforms. Since Java's layout managers aren't tied to absolute sizing and positioning, they are able to accomodate platform-specific differences among windowing systems.

119. What is the Collection interface?
The Collection interface provides support for the implementation of a mathematical bag - an unordered collection of objects that may contain duplicates.

120. What modifiers can be used with a local inner class?
A local inner class may be final or abstract.

121. What is the difference between static and non-static variables?
A static variable is associated with the class as a whole rather than with specific instances of a class. Non-static variables take on unique values with each object instance.

122. What is the difference between the paint() and repaint() methods?
The paint() method supports painting via a Graphics object. The repaint() method is used to cause paint() to be invoked by the AWT painting thread.

123. What is the purpose of the File class?
The File class is used to create objects that provide access to the files and directories of a local file system.

124. Can an exception be rethrown?
Yes, an exception can be rethrown.
125. Which Math method is used to calculate the absolute value of a number?
The abs() method is used to calculate absolute values.
126. How does multithreading take place on a computer with a single CPU?
The operating system's task scheduler allocates execution time to multiple tasks. By quickly switching between executing tasks, it creates the impression that tasks execute sequentially.

127. When does the compiler supply a default constructor for a class?
The compiler supplies a default constructor for a class if no other constructors are provided.

128. When is the finally clause of a try-catch-finally statement executed?
The finally clause of the try-catch-finally statement is always executed unless the thread of execution terminates or an exception occurs within the execution of the finally clause.

129. Which class is the immediate superclass of the Container class?
Component

130. If a method is declared as protected, where may the method be accessed?
A protected method may only be accessed by classes or interfaces of the same package or by subclasses of the class in which it is declared.

131. How can the Checkbox class be used to create a radio button?
By associating Checkbox objects with a CheckboxGroup.

132. Which non-Unicode letter characters may be used as the first character
of an identifier?
The non-Unicode letter characters $ and _ may appear as the first character of an identifier

133. What restrictions are placed on method overloading?
Two methods may not have the same name and argument list but different return types.

134. What happens when you invoke a thread's interrupt method while it is
sleeping or waiting?
When a task's interrupt() method is executed, the task enters the ready state. The next time the task enters the running state, an InterruptedException is thrown.

135. What is casting?
There are two types of casting, casting between primitive numeric types and casting between object references. Casting between numeric types is used to convert larger values, such as double values, to smaller values, such as byte values. Casting between object references is used to refer to an object by a compatible class, interface, or array type reference.
136. What is the return type of a program's main() method?
A program's main() method has a void return type.

137. Name four Container classes.
Window, Frame, Dialog, FileDialog, Panel, Applet, or ScrollPane

138. What is the difference between a Choice and a List?
A Choice is displayed in a compact form that requires you to pull it down to see the list of available choices. Only one item may be selected from a Choice. A List may be displayed in such a way that several List items are visible. A List supports the selection of one or more List items.

139. What class of exceptions are generated by the Java run-time system?
The Java runtime system generates RuntimeException and Error exceptions.

140. What class allows you to read objects directly from a stream?
The ObjectInputStream class supports the reading of objects from input streams.

141. What is the difference between a field variable and a local variable?
A field variable is a variable that is declared as a member of a class. A local variable is a variable that is declared local to a method.

142. Under what conditions is an object's finalize() method invoked by the garbage collector?
The garbage collector invokes an object's finalize() method when it detects that the object has become unreachable.

143. How are this() and super() used with constructors?
this() is used to invoke a constructor of the same class. super() is used to invoke a superclass constructor.

144. What is the relationship between a method's throws clause and the exceptions
that can be thrown during the method's execution?
A method's throws clause must declare any checked exceptions that are not caught within the body of the method.

145. What is the difference between the JDK 1.02 event model and the event-delegation
model introduced with JDK 1.1?
The JDK 1.02 event model uses an event inheritance or bubbling approach. In this model, components are required to handle their own events. If they do not handle a particular event, the event is inherited by (or bubbled up to) the component's container. The container then either handles the event or it is bubbled up to its container and so on, until the highest-level container has been tried..
In the event-delegation model, specific objects are designated as event handlers for GUI components. These objects implement event-listener interfaces. The event-delegation model is more efficient than the event-inheritance model because it eliminates the processing required to support the bubbling of unhandled events.

146. How is it possible for two String objects with identical values not to be equal
under the == operator?
The == operator compares two objects to determine if they are the same object in memory. It is possible for two String objects to have the same value, but located indifferent areas of memory.

147. Why are the methods of the Math class static?
So they can be invoked as if they are a mathematical code library.

148. What Checkbox method allows you to tell if a Checkbox is checked?
getState()

149. What state is a thread in when it is executing?
An executing thread is in the running state.

150. What are the legal operands of the instanceof operator?
The left operand is an object reference or null value and the right operand is a class, interface, or array type.

151. How are the elements of a GridLayout organized?
The elements of a GridBad layout are of equal size and are laid out using the squares of a grid.

152. What an I/O filter?
An I/O filter is an object that reads from one stream and writes to another, usually altering the data in some way as it is passed from one stream to another.

153. If an object is garbage collected, can it become reachable again?
Once an object is garbage collected, it ceases to exist. It can no longer become reachable again.

154. What is the Set interface?
The Set interface provides methods for accessing the elements of a finite mathematical set. Sets do not allow duplicate elements.

155. What classes of exceptions may be thrown by a throw statement?
A throw statement may throw any expression that may be assigned to the Throwable type.

10 Simple Steps to Learn English for Job

2008-12-30T04:14:00.002-08:00

Learning any new language takes a lot of dedication, practice and time. But all of that pays off when you are able to express yourself in an exciting new way. Learning English has limitless advantages.

Job markets increase, grades go up and new friends are made. You will benefit greatly from learning English simply because so many people speak the English language. New horizons and opportunities will expand before your eyes. Use the following tips to help you in your language learning process for your job.

? Have desire –Want to learn a new language. Learning English requires lot o f study and dedication. Only true desire will keep you motivated.

? Know your motive –Why do you want to learn English? Is it to help you in school, your business or something else? Identify your reason and remember it when you are having a hard time.

? Set goals –Set goals for yourself whether it be learning twenty words a week or giving a presentation in English at work next month. Goals will keep you motivated.

? Study a little each day –Studying formally for at least 30–60 minutes a day will help you retain what you learn. At the beginning of each study session, review what you learned in the lesson before.

? Make a set study schedule –Set aside a specific time for study each day. That way you are less likely to skip your lessons.

? Study out loud –Pronounce the words out loud to yourself as you study. You will remember them more easily and you will be able to practice your pronunciation at the same time.

? Use different learning methods –Language can be learned through different activities such as speaking, reading, writing, and associating pictures with words. Find out which method works best for you and use a variety of other methods for practice.

? Practice speaking –Practice the language you have learned as much as possible.

? Don't be afraid –Never be afraid to try speaking to other people even if you don’t know everything. They will appreciate your efforts.

? Surround Yourself –Surround yourself with English. Read it, listen to it, watch it and speak it with others.

Start Practising to do these points before you face an interview

? Listen to native speakers –Pay careful attention to native speakers using English. Observe the way they pronounce the words and how they use them.

? Pronunciation is key –Imitate native English sounds as closely as you can. The more closely you pronounce words like native speakers, the better you will be understood.

? Use good resources –Use dictionaries, workbooks, software and any other resource that will allow you to practice and expand your language.

? Use what you know –Even if you know relatively little English, you should use what you know. You will be surprised at how much you can communicate with a few words or phrases.

? Speed it up –Get used to listening to the language at normal speed. It will seem fast at first, but the more you know, the more it will sound normal.

? Don't get stuck –If you don’t know a certain word, work your way around it. Use different words and actions to explain it, but don’t give up.

? Have fun! –Learning a new language is fun and exciting. Recognize your progress and use your language for ultimate enjoyment.

How To Improve Communication Skills?

2008-12-30T04:14:00.001-08:00

verbal communication skills voice plays an important role

In the case of verbal communication skills voice plays an important role. After all, one maybe knowledgeable in their domain area, but conveying their knowledge may seem like a mammoth task. This is the reason why, as a part of communication skills training there is ample emphasis laid on voice culture.

One aspect of culturing the voice is understanding intonation. This is the rise and fall in pitch, which occurs as we speak. There are various patterns of intonation. For instance, there is singsong, monotone, jump up and step down (JUSD), etc. When one intonates one puts music, melody and rhythm into the way they speak.

Basically, intonation follows certain guidelines that help one decide which are important and key ideas on which one needs to rise and fall in pitch. When one follows these guidelines, one can clearly communicate to the listener the important idea/s in the message.

The following are the various factor that can help one to modulate well and gain correct intonation, inflection and syllable stress...

Be enthusiastic
Avoid speaking in a monotone
Exaggerate voice inflection
Pause to create effect
Pace between fast and slow
Modulate between high and low pitch
Bring power with the play of volume - loud and soft
Enunciate the words to bring about clarity
Match tone with attitude

Advantages and Disadvantages of Java Collection Framework

2008-12-30T04:13:00.001-08:00

Advantages and Disadvantages of the Collection Framework

In this section, you will learn the advantages and disadvantages of Java Collection Framework. A collection is simply an object that groups multiple elements into a single unit. It is also called as a container sometimes. It is used to store, retrieve, manipulate, and communicate aggregate data. Typically, it represents data items that form a natural group and allows duplicate elements while others do not. It consists of both ordered and unordered elements.

Advantages of collections framework:

1. We need not to learn multiple ad hoc collection APIs.
2. It provides a standard interface for collections that fosters software reuse and also provides algorithms to manipulate them.
3. Reduces the effort required to design and implement APIs by eliminating the need to produce ad hoc collections APIs.
4. It provides useful data structures and algorithms that reduces programming effort due to which we need not to write them ourselves.
5. It provides high-performance implementations of useful data structures and algorithms that increases the performance.
6. Helps in establishing a common language to pass collections back and forth that provides interoperability between unrelated APIs.
7. Collection is resizable and can grow.

Disadvantages of collections framework:

1. It must cast to correct type.
2. It can't be done compile-time type checking.

Computer Networks - Frequently Asked Questions

2008-12-30T04:09:00.000-08:00

1.) What is The A Port Number?

A Port Number is allocated by the operating system (or can be requested) , in such a way to identify the pocess in a standalone system or a network.default Port Number for FTP is 21.

2.) What is a default gateway?

The exit-point from one network and entry-way into another network, often the router of the network.

3.) What is DHCP?

DHCP is a protocol which is designe for Automatic Give the IP Address to DHCP client.. DHCP Assine the IP Address for few days Lease & capture the clients MAC address.. It is Updated version of BootP…

4.) What is a default gateway?

The exit-point from one network and entry-way into another network, often the router of the network.

5.) How do you set a default route on an IOS Cisco router?

ip route 0.0.0.0 0.0.0.0 x.x.x.x [where x.x.x.x represents the destination address]

6.) What is the difference between a domain local group and a global group?

Domain local groups grant permissions to objects within the domain in which the reside. Global groups contain grant permissions tree or forest wide for any objects within the Active Directory

7.) What is LDAP used for?

LDAP is a set of protocol used for providing access to information directories.

8.) What tool have you used to create and analyze packet captures?

Network Monitor in Win2K / Win2K3, Ethereal in Linux, OptiView Series II (by Fluke Networks).

9.) What is the significance of the IP address 255.255.255.255?

The limited broadcast address is utilized when an IP node must perform a one-to-everyone delivery on the local network but the network ID is unknown.

Computer Architecture Basic Questions for Interview

2008-12-30T04:08:00.000-08:00

1.) What is Virtual Memory?

This Memory is used extending the capability of physical memory. This memory is simulated by the hard drive.When all the RAM is being used the computer will swap data to the hard drive and back to give the impression that there is more memory

2.) What are the five stages in a DLX pipeline?

Instruction Fetch Stage Instruction Decode Stage Instruction Execution Stage Memory Stage Write Back

3.) What is MESI?

MESI is a Cache Coherency protocol used in multi-processor systems to indicate the state in which the data in the cache of a particular processor is. It stands of Modified, Exclusive, Shared and Invalid

4.) What is cache memory?

Cache memory is random access memory (RAM) that a computer microprocessor can access more quickly than it can access regular RAM. As the microprocessor processes data, it looks first in the cache memory and if it finds the data there (from a previous reading of data), it does not have to do the more time-consuming reading of data from larger memory.(cache memory is used between the c.p.u and the ram to access dta fastly)

5.) What is hard disk and what is its purpose?

Hard disk is the secondary storage device, which holds the data in bulk, and it holds the data on the magnetic medium of the disk.Hard disks have a hard platter that holds the magnetic medium, the magnetic medium can be easily erased and rewritten, and a typical desktop machine will have a hard disk with a capacity of between 10 and 40 gigabytes. Data is stored onto the disk in the form of files.

6.) What’s the speed and device maximum specs for Firewire?

EEE 1394 (Firewire) supports the maximum of 63 connected devices with speeds up to 400 Mbps.

7.) What’s the difference between L1 and L2 cache?

Level 1 cache is internal to the chip, L2 is external. L1 Cache is of Higher speed than that of L2 Cache.

8.) What is the difference between primary & secondary storage device?

In primary storage device the storage capacity is limited. It has a volatile memory. In secondary storage device the storage capacity is larger. It is a nonvolatile memory. Primary devices are: RAM / ROM. Secondary devices are: Floppy disc / Hard disk.

Frequently Asked C/C++ Questions

2008-12-30T04:06:00.000-08:00

C / C++ - Frequently Asked Questions

1.) How To Split an Image File In C Launguage?

To split an image file various logics are there.the best logic in such a way that take the size of the file using c file functions and split into the pieces how many required by asking the input.

2.)What is the difference between an ARRAY and a LIST?

Array is collection of homogeneous elements. List is collection of heterogeneous elements. For Array memory allocated is static and continuous. For List memory allocated is dynamic and Random. Array: User need not have to keep in track of next memory allocation. List: User has to keep in Track of next location where memory is allocated.

3.)Define a constructor - what it is and how it might be called?

constructor is a member function of the class, with the name of the function being the same as the class name. It also specifies how the object should be initialized

4.)Define a constructor - what it is and how it might be called?

constructor is a member function of the class, with the name of the function being the same as the class name. It also specifies how the object should be initialized Ways of calling constructor:
1) Implicitly: automatically by complier when an object is created.
2) Calling the constructors explicitly is possible, but it makes the code unverifiable.

5.)You have two pairs: new() and delete() and another pair : alloc() and free(). Explain differences between eg. new() and malloc()?

1.) “new and delete” are preprocessors while “malloc() and free()” are functions. [we dont use brackets will calling new or delete].
2.) no need of allocate the memory while using “new” but in “malloc()” we have to use “sizeof()”.
3.) “new” will initlize the new memory to 0 but “malloc()” gives random value in the new alloted memory location [better to use calloc()].

6.)Explain term POLIMORPHISM?

POLYMORPHISM : A phenomenon which enables an object to react differently to the same function call. in C++ it is attained by using a keyword virtual

7.)What are 2 ways of exporting a function from a DLL?

1.Taking a reference to the function from the DLL instance.
2. Using the DLL ’s Type Library

8.)Describe PRIVATE, PROTECTED and PUBLIC – the differences?

The Difference Between The private Public And Protected member are: public methods/attributes are accessible to all classes. protected are accessible to class and derived classes. private are only for class (not for derived classes)

J2ME Cryptography

2008-12-29T17:15:00.000-08:00

The absence of standard and familiar Java APIs presents one of the biggest obstacles when developing for Java 2 Micro Edition (J2ME). Since J2ME targets much smaller devices, it lacks many libraries and features that are normally available in larger Java installations.

On Java 2 Standard Edition (J2SE) and Java 2 Enterprise Edition (J2EE), the Java Cryptography Architecture and Java Cryptography Extension help streamline the process of adding security to a project. The J2ME platform, however, lacks crypto APIs.

Of course, many J2ME devices, such as Palm handhelds, aren't suited for common cryptographic functions. Their constrained RAM and processors can make operations, such as public key cryptography, infeasible. Still, there's a real need for security on small devices, and they can perform a useful subset of cryptographic operations.

This article explores the use of cryptography on J2ME devices and walks though an implementation of a simple password-based encrypted database program. The database holds user login information and can be used to manage accounts for different machines and Web sites. Although the example targets J2ME for Palm handhelds, its design maximizes portability.

Ciphers
Ciphers are algorithms that use a key to transform a message (plaintext) into an encrypted message (ciphertext) or vice versa. Symmetric ciphers rely on a single key for both encryption and decryption. DES, TripleDES (also called DESede), and Blowfish are symmetric ciphers. All three operate on 64-bit input blocks and produce 64-bit output blocks.

Modes are applied to ciphers to define their behavior. In the simplest mode, Electronic Code Book (ECB), each input block always produces the same output block. Although this makes implementation simple, the one-to-one mapping of input to output leaves the ciphertext vulnerable to attacks. Patterns in the encrypted data become apparent in the ciphertext if there are repeated input blocks, making cryptanalysis much easier.

The cipher block chaining (CBC) mode strengthens the ciphertext by making each block of ciphertext dependent on both the corresponding block of plaintext and all previous plaintext blocks as well. It uses an XOR feedback register to modify the plaintext before encrypting and after decrypting. At the start of an encryption or decryption operation, the XOR register is set to a randomly generated initialization vector (IV) that's transmitted or stored along with the ciphertext. It's not terribly important that the IV is truly random, but it should be different each time plaintext is encrypted with the same key.

Since plaintexts might be any length, extra bytes must be added to pad the input to a multiple of the block size in length. Public Key Cryptography Standard #5 (PKCS#5) padding is the most common padding scheme for symmetric block ciphers.

Choosing appropriate ciphers for J2ME requires special care, since most J2ME devices have relatively slow processors. Table 1 shows some rough benchmarks for a PalmV. The key setup column gives the time it takes for an algorithm to initialize itself with a key. The encryption column shows the amount of time it takes to encrypt one block (8 bytes) of data. Naturally, different implementations of the algorithms will have different performance. The data in Table 1 is by no means a definitive performance analysis.

For these implementations, TripleDES and Blowfish take significantly longer to initialize than DES, but Blowfish encrypts data faster than DES or TripleDES. Depending on the application, either key setup or encryption might dominate the running time. Choosing an appropriate cipher always involves weighing the trade-off between performance and the desired level of security.

Hashes, Passwords, and Keys
Hash algorithms are one-way functions that turn an arbitrary message of bytes into a fixed-length digest, or fingerprint, usually not much more than a dozen bytes long. Good hash algorithms should be collision-resistant, making it computationally infeasible to derive the original message from the digest. Even a minor change in the input should drastically change the resulting fingerprint. MD5 and SHA1 are two commonly used hash functions.

Applications commonly use hash functions to transform user-supplied passwords into symmetric keys. Several standards define techniques to convert passwords, but PKCS#5 specifies a simple technique: convert the password string to a byte array and use it as the input to a hash algorithm. The resulting digest serves as the key.

Running the password through a hash function serves several purposes. First, the hash function transforms variable length passwords into uniform-length hashes. Also, character strings follow certain patterns and good symmetric keys should be as close to random bytes as possible. Hashing the password removes the patterns, making cryptanalysis much harder.

Using a password-based key means that the key is only as secure as the password. If the number of likely passwords is smaller than the total number of keys, it's more efficient to search through all possible passwords than to attack the key directly. It's pointless to use a cipher with a huge key space unless users choose long passwords or passphrases. DES has a key space of 64 bits, of which only 56 are actually used. That's roughly equivalent to randomly selecting nine characters from the set upper- and lowercase letters and numbers. Users are unlikely to choose passwords longer than that for J2ME programs since text entry is typically inconvenient.

The dictionary attack is a common way to attack password-based systems. In it an attacker computes a list of keys from a dictionary of likely passwords. Once the attacker has obtained the encrypted data, he or she uses each potential key to decrypt the ciphertext until one of them produces meaningful plaintext.

A technique called salt helps guard against dictionary attacks. Salt is a set of random bytes that are stored unencrypted along with the ciphertext and are added to the password before it's hashed. It prevents an attacker from precomputing a list of keys since the password dictionary generates a different set of keys for each different salt value. Salt doesn't completely defeat a dictionary attack, but it does make it much more computationally intensive.

Implementing an Encrypted Password Database
Deploying on J2ME requires a virtual machine, configuration, and profile. Sun's KVM is the most compact virtual machine that fulfills the J2ME requirements. Configurations define a set of APIs for use on certain classes of devices. For example, the Connected Limited Device Configuration (CLDC) targets compact devices, such as cell phones and PDAs. Profiles extend the configuration and add functionality applicable to a particular domain. As of this writing, the Mobile Information Device Profile (MIDP) is the only profile that's been finalized. It contains functionality intended for cell phones and two-way pagers.

The primary design goal for this application is to make it as simple as possible to port to different J2ME configurations and profiles. As presented, it targets the CLDC and a PalmOS-specific profile. It contains two device-specific groups of functionality: the GUI and the storage mechanism. The design accommodates different GUIs by separating the application's business logic and presentation. It solves the device-dependent storage problem using the Template pattern. An abstract superclass relies on methods in the concrete subclasses to store the data.

Another important goal is maintaining acceptable performance on the target device. Therefore, the design encapsulates the usage of the computationally intensive algorithms in a single class. Swapping in alternate hash functions or encryption algorithms makes it possible to customize the program for the performance characteristics of different devices. For this application, SHA1 and DES provide reasonable performance and are as secure as the expected passwords (see Figure 1)

Cryptographic Algorithms
The supplied code includes DES and SHA1 implementations in the crypto package. Both take care of padding the input data if needed. The SHA1 class uses the padding defined by the SHA1 algorithm and DES uses PKCS#5 padding and CBC mode. The algorithms' inner workings are beyond the scope of this article. Other sources, such as Applied Cryptography by Bruce Schneier, discuss the algorithms and cryptanalysis in detail.

The DES class throws a CipherException if it encounters a problem encrypting or decrypting. Possible problems include invalid parameters (like an IV that's not 8-bytes long or attempting to decrypt an array that's not a multiple of 8 bytes in length) and invalid padding after decryption. Normally, using the wrong key or IV will result in improperly padded plaintext.

Data Objects
Two data classes, SiteList and SiteInfo, encapsulate the user's information. SiteList keeps track of all the SiteInfos, each of which stores an individual site's profile. Since J2ME doesn't support serialization natively, the classes handle saving and restoring their own state in their load() and save() methods. They use simple byte-array structures as shown in Figure 2.

The SiteInfo class wraps four strings: the site's name, location, username, and password. Each setter method trims the string to ensure it will be less than 127-bytes long (Java's maximum byte value). The class handles serializing its location, username, and password.

The SiteList class keeps track of all the SiteInfos in the system. It holds all the SiteInfos in a vector and is responsible for storing their name strings when it's serialized.

Since hashing the user's password, setting DES up for decryption, and decrypting the data are all computationally intensive operations, it's important to decrypt information only as needed. Keeping the site names in one byte array allows the application to start up faster because the application needs to display only the site names at startup. It can wait until the user selects a particular site to load and decrypts the rest of the SiteInfo data.

Persistent EncryptedStorage
The abstract class EncryptedStorage handles the application's cryptography. It turns the password and salt into a DES key and deals with encrypting and decrypting the serialized SiteList and SiteInfos. When saving data it first creates an initialization vector. Then it encrypts the plaintext bytes and concatenates the IV with the ciphertext. EncryptedStorage then uses the Template pattern and calls an abstract method to store the combined array in the device's storage system. The class gets random bytes from java.util.Random, which produces bytes that are random enough for salt and IV values, but not for keys. Listing 1 shows the code that does the hashing and encrypting.

In this case, PalmEncryptedStorage subclasses EncryptedStorage and talks directly with the Palm's storage system, the database. The Palm-specific classes include com.sun.kjava.Database, a class that permits access to an application's database on the Palm, stored in a set of records. At startup the PalmEncryptedStorage checks if it has already created a database. If not, it makes a new one, generates salt, and stores it in record 0. The IV and ciphertext for the SiteList go in record 1. SiteInfos get stuffed into subsequent records. The SiteInfo at index 0 in the SiteList is kept in record 2, index 1 is kept in record 3, and so forth.

Listing 2 illustrates how the PalmEncryptedStorage interacts with the Palm's database. Three values identify each database: a creator ID (managed by Palm Computing at www.palmos.com/dev/tech/palmos/creatorid/), a database type ID, (separates different applications from a single creator ID), and a database type string (shown in the list of databases in the Palm's memory-usage list).

The class's constructor tries to open an existing database. If it can't find one, it creates a new one, opens it, and stores the 8-byte salt value. The setRecordBytes() method sets the bytes of the specified record index. If a record at that index already exists, it's overwritten; if no record exists, a new record is appended.

User Interface
A class called com.sun.kjava.Spotlet draws the GUI and handles user input. Event handling is very different from Swing's event handling. A Spotlet must register itself to receive user input events and only one can be registered at a time. For stylus events, the Spotlet gets the (x, y) coordinates and must interrogate each GUI widget to see if it occupies those pixels and then acts appropriately. For example, if a user clicks on a text field it should get the focus. For text input, the Spotlet must check if any of the GUI components have the focus and then pass it to that component. Listing 3 is a code snippet from SiteListSpotlet that does event handling.

In this program an abstract class, AbstractSpotlet, draws the familiar Palm UI tab at the top of the screen to show the user which application is running. It also keeps a reference to the PalmPassword object so that the Spotlet can interact with the rest of the application. There are three subclasses, one for each screen in the UI.

The first is the LoginSpotlet. It gets the password from the user and informs him or her if the password was not correct. SiteListSpotlet shows the list of sites and permits the user to either select one to display or create a new entry (see Figure 3). The SiteInfoSpotlet allows the user to view and edit a site's information and then save it (see Figure 4).

Unfortunately, the Palm-specific classes don't include a list GUI widget. The ListBox class provided works like list boxes in other Palm applications. It's backed by a ListBoxModel that supplies the data to be displayed and sends selection events to a ListBoxListener. It calculates the number of elements that can fit vertically, based on the size of the box, and draws as many elements from the ListBoxModel as can fit. It uses the Palm-specific ScrollBar widget to handle scrolling, shifting the elements displayed in response to user input. If the user selects one of the elements in the list, the ListBox notifies its ListBoxListener that an element in the list was selected.

The PalmPassword class contains the main method for the application and acts as a controller for the system. It instantiates the three Spotlets that all keep a reference to the PalmPassword object. When the Spotlets get events from the user, they call methods in the controller to process the request and display other Spotlets as needed.

Building and Running the Application
Building an application for J2ME devices takes a few more steps than building for J2SE. J2ME runtime environments work with the same Java compilers as J2SE. Two additional steps are needed though: preverifying the class files and building the preverified files into a Palm application. Preverification checks each class file to make sure it's a valid Java class file, and stores verification information in it. This minimizes the amount of verification the KVM needs to do, improving runtime performance.

Setting up an IDE or a build tool to handle the process will save a lot of time, as will installing an emulator for the target device on the development workstation. Sun provides detailed installation and usage instructions for the J2ME libraries and utilities.The page also describes how to get a Palm emulator and transfer a ROM image from a Palm device.

Unfortunately, the section labeled "The J2ME CLDC Development Environment" contains a couple of errors. So run the following commands from the c:\j2me_cldc\tools\palm\ directory instead:

md classes
javac src\palm\database\*.java -d classes
copy src\palm\database\DefaultTiny.bmp
classes\palm\database
copy src\palm\database\Wrapper.prc
classes\palm\database

The build.bat file included with the source compiles the source code, preverifies the compiled classes, stores the results in .\preverified, and builds them into a Palm application. Be sure to edit the first line of the batch file to point to the proper directory. After installing the KVM as documented by Sun, simply drag-and-drop PalmPassword.prc onto an emulator or HotSync it to a Palm device and run it.

Summary
The code provided with this article can be downloaded from the JDJ Web site. It gives a solid base for cryptography in J2ME and shows how to separate device-specific code from the main application logic, both for the GUI and for persistent storage. In addition, it provides an implementation of password-based encryption without relying on other APIs. Different hash and encryption algorithms can easily be swapped in to increase the cryptographic security of the data.

Although the example program is functional, it's still far from feature-complete. As presented there's no way to delete a SiteInfo from the list or sort the list. The application could give the user some sort of progress bar during the password hashing and key setup. More fields might be added to let the user input more information about a site, or the ListBox could be changed to display more than just the site's name. Also, if something goes wrong with encryption or decryption, it would be nice to inform the user instead of just swallowing the exception.

A conduit that synchronizes data with an application on the user's desktop machine might also be useful. Because all the device-specific code is kept isolated, it would be simple to create a Swing-based application that could read the encrypted data and allow the user to manage the password database.

It's important to remember that cryptography doesn't automatically make a system secure. For this application, a poorly chosen password will reduce the security significantly. Also, it's necessary to exit the program after use or the passwords will be vulnerable to anyone who happens upon the device. Even the best security is still only risk management.

Just posted is a follow-up to my article in the current issue of JDJ, describing how to port my application to MIDP and including the full source code. The link is available at http://www.isnetworks.com/j2meCrypto/. This is a follow-up to "J2ME Cryptography," an article published in the July 2001 issue of Java Developer's Journal.
Published Jul. 1, 2001— Reads 14,620
Copyright © 2008 SYS-CON Media. All Rights Reserved.

Listing 1
public void init( String password ) {
byte[] toBeHashed = concat( getSalt(),
password.getBytes() );
byte[] hash = mSHA1.digest( toBeHashed );
byte[] keyBytes = new byte[ 8 ];
System.arraycopy( hash, 0, keyBytes, 0, 8 );
mDES.setKey( keyBytes );
}

private byte[] encrypt( byte[] plaintext )
throws StorageException {
try {
byte[] iv = getRandomBytes( 8 );
byte[] ciphertext = mDES.encrypt( plaintext,
iv );
return concat( iv, ciphertext );
}
catch( CipherException e ) {
throw new StorageException( e.getMessage() );
}
}

Listing 2
public PalmEncryptedStorage() {
mDatabase = new Database( DB_TYPE_ID,
CREATOR_ID, Database.READWRITE );
if ( !mDatabase.isOpen() ) {
Database.create( 0, DB_TYPE_STRING,
CREATOR_ID, DB_TYPE_ID, false );
mDatabase = new Database( DB_TYPE_ID,
CREATOR_ID, Database.READWRITE );
mDatabase.addRecord( getRandomBytes( 8 ) );
}
}

private void setRecordBytes( int recordNumber,
byte[] bytes ) {
if ( mDatabase.getNumberOfRecords() <=
recordNumber ) {
mDatabase.addRecord( bytes );
}
else {
mDatabase.setRecord( recordNumber, bytes );
}
}

Listing 3
public void penDown( int x, int y ) {
if ( mListBox.contains( x, y ) ) {
mListBox.handlePenDown( x, y );
}
else if ( mNewButton.pressed( x, y ) ) {
mPalmPassword.showSiteInfo( new SiteInfo() );
}
}

public void penMove( int x, int y ) {
if ( mListBox.contains( x, y ) ) {
mListBox.handlePenMove( x, y );
}
}

J2ME Basics

2008-12-28T17:26:00.000-08:00

J2ME: Micro Java

Beyond the desktop and enterprise, Java may be found on small devices ranging from smart cards to PDAs to television set-top boxes. These micro devices typically are categorized as either low-end or high-end devices. Low-end devices (such as mobile phones and entry-level PDAs) support less-powerful microprocessors and less memory than their high-end counterparts (for example, television set-top boxes and more capable PDAs). Furthermore, a low-end device's network connections tend to be intermittent and, unlike those of a high-end device, don't have a large network bandwidth. To support Java on all micro devices, Sun developed J2ME.

J2ME's collection of highly optimized Java 2 Platforms addresses the needs of micro devices. Most J2ME platforms support the configuration and profile concepts:

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Configuration: Combination of virtual machine and a minimal set of class libraries, providing base functionality for a range of similar micro devices
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Profile: Higher-level class libraries that further define application lifecycle, user interface, and device-specific properties access

There currently are two J2ME configurations: Connected Limited Device Configuration (CLDC) and Connected Device Configuration (CDC). CLDC, the smaller configuration, targets low-end devices with 16-bit or 32-bit microprocessors and 128–512 kilobytes of memory for a Java implementation and applications. CLDC supports two Sun virtual machines: the original Kilobyte Virtual Machine (KVM)—a term derived from CLDC's support of micro devices that have memory measured in kilobytes—and the newer (and higher-performance) CLDC HotSpot Implementation virtual machine, which supports 32-bit microprocessors with 512KB to 1MB of memory. In contrast, CDC targets high-end devices with 32-bit microprocessors and at least 2MB of memory for a Java implementation and applications. Unlike CLDC, CDC supports Sun's Consumer Virtual Machine (CVM) and a larger subset of the J2SE standard class library. Although many vendors license Sun's KVM, CLDC HotSpot Implementation, and CVM virtual machines, other vendors may substitute their own compatible virtual machines for CLDC/CDC configurations.

Although vendors can create their own profiles, Sun provides its own standardized profiles. Sun's standard profile for CLDC is the Mobile Information Device Profile (MIDP). The MIDP offers the core functionality (user interface, network connectivity, application management, and local data storage) required by mobile applications. In contrast, CDC's standard profiles are Foundation, Personal, and Personal Basis:

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The Foundation profile provides a foundation (with network and no user interface support) for the other two profiles, which layer themselves on top.
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The Personal profile provides devices with full GUI/Internet applet support, and includes the complete AWT.
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As a subset of Personal, the Personal Basis profile provides limited user interface support, but supports specialized graphics toolkits.

J2ME has elicited much interest among Java developers. Probably the two areas of most interest are the creation of MIDLets (J2ME applications that run in a CLDC/MIDP environment) and J2ME's support for wireless application development.

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