Hi HaoZhe,
The "runme.jar" file normally exists
inside the jar file you will submit to Sun. It is this second jar file - the one that you send to Sun - that we are talking about in this
thread.
Take a look in your instructions under the heading "Packaging of Submissions".
You should have text similar to:
All elements of your submission must be packaged in a single JAR file. The JAR file must have the following layout and contents in its root:
The executable JAR containing the programs. This must be called runme.jar....
See how the "runme.jar" file is inside the submission jar?
Regards, Andrew