java executable

creating a executable jar is better option

A new and cool feature of Java2 is the ability to create executable jar files. A jar file is simply a file containing a collection of java files (typically, java .class files, but any other kind of file could be included as well). To make a jar file executable, you need to specify where the "main" Class is in the jar file, so the "java" command knows what main() method to invoke to get the software going. The procedure is quite simple, and this document provides step-by-step instructions. For more details on jar files, consult http://java.sun.com/docs/books/tutorial/jar/.

   1. First, make sure you have installed Java 1.2 or above. This facility is not available in previous versions of Java.

   2. Next, create your working java system. In general, you will want to put it into a package. For this example, I created a trivial HelloWorld application that prints out "Hello World" plus the first command line argument, and placed it into the package "psae". Therefore, the HelloWorld files (HelloWorld.class, HelloWorld.java) were located in the directory psae. I tested the system to make sure it worked before going on to the next step.

   3. In the directory in which the psae is located, created a file called "mainClass". This file contains a single line specifying where the main Class is to be found in the jar file. Note that I use the package specification. Here is the single line:

Main-Class: psae.HelloWorld

      Note: make sure you type a carriage return after this line; some windows systems need it and will report a "Failed to load Main-Class manifest attribute" error.

   4. Next, I create a jar file called psae.jar using the "jar" command in Java2. I use the "m" command line argument to specify the manifest file mainClass, which adds information to the jar file on where the main class will be found. Here is the jar command:

bertha:~ > jar cmf mainClass psae.jar psae

   5. Just for fun, and to check what's happened, I print the table of contents for the jar file I just created. Here's the command and its result:

bertha:~ > jar tf psae.jar
META-INF/
META-INF/MANIFEST.MF
psae/
psae/HelloWorld.java
psae/HelloWorld.class

   6. Having successfully created the jar file, I can now invoke java2 on it with the command line argument:

bertha:~ > java -jar psae.jar Philip
Hello World Philip

well I have JDK 1.4 which I downloaded with JBuilder...will that work for me?

>>To make a jar file executable, you need to specify where the "main" Class is in the jar file,
I'm not sure exactly what you mean..Al I know is I have a jar file and a manifest that says version 1.0 and in the second line it has my main class name..Is that what you mean?

I guess what you are saying is I should create the manifest myself then to make sure there is a carrige return right?

>> I guess what you are saying is I should create the manifest myself then to make sure there is a carrige return right?

True

>>I'm not sure exactly what you mean..Al I know is I have a jar file and a manifest that says version 1.0

Create your own Mainifest File and Place line something like following
Main-Class: psae.HelloWorld

where HelloWorld is a main class and psae package

>> well I have JDK 1.4 which I downloaded with JBuilder...will that work for me?

Yes it will

can I create a manifest file from an ordinary text file? using notepad or something?

>> can I create a manifest file from an ordinary text file? using notepad or something?

Yes you can. It is just a text file

ok I will try it

hasnt worked yet :(

sudhakar_koundinya,

You really shouldn't copy and paste from the internet, and then try to take credit for it! Provide a link instead: http://csdl.ics.hawaii.edu/~johnson/613f99/modules/04/jar-files.html , be honest.

>>You really shouldn't copy and paste from the internet, and then try to take credit for it! Provide a link instead:

I knoow that friend. Generally along with the matter I copied, I do post the link also. I forget that this time.

Generally  I do this because of two reasons.

1. Instead of opening two pages (Question thread and reference url), I do think that it will be easy to get the information with in same page

2. Some times in the older threads of EE, if I try to open the referenced links , I do get page not found errors. Like that I do missed maximum information (for the questions I answered and I asked)- Some times Very good Stuff. That is the reason, although content is duplicated, I do post  the content from URL.

Just because of not posting the link, this makes you to to think that I am not honest :((

Regards
Sudhakar

orangehead911 thanks for the link..the program was very helpfull

thanks

My pleasure! =-)