If you want to modify the grammar, you'll need JavaCC.
An enlightened IDE: JBuilder This program was written with Inprise/Borland's excellent JBuilder Client/Server development environment.
DocWiz is mentioned in Sun's Javadoc FAQ, also a must read document.
It got a mention in The Software View
Developer.com calls DocWiz "Useful" and gives it one of those little fan icons:
Universe - the ultimate space strategy game uses DocWiz for development.