Depending on your needs. I've tried several of them, but they don't sound exactly like what you want.

Jedit is a program editor that seems to do well written in java so it should run on Linux as well. Its meant for stand alone work i.e. one program or project at a time.

NetBeans and Ecllipse are true IDEs more for hardcore dev work than playing around. I personally like ecllipse because the data handling and searching works for just about anything you want! You can organize your class notes with the same program you write with!

All of theses have decent size dev communities with growing numbers of plug-ins as well.