This looks right, assuming you have a class in the jar named
Test, which is in the default package, and has a main method. You could test it from the command line using:
java -jar the.jar
If you want it to run by clicking an icon, then the problem might be what action you associate to an executable jar. It's been awhile since I've done standalone java programs, but it seems to me there is a regular "java" command and "javaw". The purpose of "javaw" is to run GUI-based program where you don't want a command prompt window to open. If that's what you're using, that could be your problem.