Distribute a java program to others

If possible, collect all your .java files and .class files (and anything else you want to include) together in a single directory.
Using a text editor, create a file (say, myManifest) containing the following lines:

Manifest-Version: 1.0
Main-Class: MyMainClass

where MyMainClass is the name of the class containing the main method you want to use.
From the command line, execute the command:

jar cvfm myResult.jar myManifest *.java *.class

where myResult.jar is the jar file you are trying to create, myManifest is the file you created in step 2, and everything else is the files you want to include.

On Microsoft Windows systems, the Java 2 Runtime Environment’s installation program will register a default association for Jar files so that double-clicking a Jar file on the desktop will automatically run it with javaw -jar. Dependent extensions bundled with the application will also be loaded automatically. This feature makes the end-user runtime environment easier to use on Microsoft Windows systems.