I have good experience with Jadclipse - http://jadclipse.sourceforge.net/wiki/index.php/Main_Page - there is an update site at http://jadclipse.sf.net/update
For best results, use jad and configure it to list line numbers as comments which will enable the output where the code is on the correct line. This is best for debugging sessions.
Then set it to be the default view for classes. See the documentation for details. This works well for me.
