Java code to an executable?

[abo sager]

How can I convert a java code to an executable file? I mean to a .jar file.

For example, an assembly code can be converted to .exe by the order MASM and then LINK.

I know how to compile the code in the DOS by JAVAC and then executing using the order JAVA .

But how can i make it an executable file without the need of the code? Is there a way that it can be a .EXE file?

[egrath]

Hi,

when you compile your java sourcecode you get a bunch of .class files which contain the executable code interpreted by the java interpreter. In order to stuff these .class files together to a jar file (java archive) you have to use the tool "jar.exe" which is installed with the SDK.

You also need a so called "manifest" file which describes in which class File inside the jar archive the main method exists.

Example:

suppose you have a simple "hello, world!" program which consist of the following code:

class hello
{
        public static void main( String[] args )
        {
                System.out.println( "Hello, World!" );
        }
}

when you now compile this program using "javac hello.java" you get the file "hello.class" which you can execute by typing "java hello".

To create a Jar Archive first create a file called "manifest" which contains the following content:

Main-Class: test

now create the jar file:

jar cvfm hello.jar manifest hello.class

and execute your jar file with:

java -jar hello.jar

If you want to create a .exe File you have to write a wrapper in a native language like c or c++. See one of my posts in this Forum below.

Egon

[hmaster10]

i get a "Failed to load Main-Class manifest attribute from file.jar"

should the manifest file be save without an extension?

edit: Found the error. there should be a new line after the main-class: test

main-class: test
<enter>

Edited March 26, 2006 by hmaster10

[LLXX]

Java is a semi-compiled interpreted language, so it must be run under the Java VM. I guess you could use a wrapper around the bytecode like .NET does, but the Java VM itself is rather huge...