Jad Decompiler Plug-in for Eclipse

JAD Eclipse is an eclipse plug-in for the JAD Decompiler. The following is a quick description of how to setup JAD Eclipse (assuming you already have eclipse setup).
Download the latest version of JAD decompiler and set modify your path to add JAD_HOME directory.
Download the latest version of JAD Eclipse from the link shown above and extract it to your eclipse plugins directory.
Restart eclipse and configure JAD as follows
In eclipse, go to - Window->Preferences->Java->JadClipse
Set Path to decompiler to "jad" (jad is already in your path).Click Apply.This is the basic setup for running JAD Eclipse. You will be able to look in to you library classes by simply clicking on the class file, or the class in the type hierarchy. If you are in the J2EE perspective, you can open up you jar files and look into those class files too. It is up to you to decide how you want to go. By the way, JAD eclipse also has a lot of additional customizations available, which can be seen under JAD Eclipse preferences in Eclipse.