Hello rance,

There's a couple steps to it. First you have to extract the contents from the jar file to see the .class files, then run the .class files through a decompiler to see the Java Code.

For Step 1 this link will help:
http://docs.oracle.com/javase/tutorial/deployment/jar/unpack.html

For Step 2 this link will help:
http://java.decompiler.free.fr/?q=jdgui

I've utilized Java Decompiler in the past and it's worked great.

Kris

you also use jdk i think Dj java decompiler is good  but jdk compiler is batter than dj java