Half-strength java IDEs

These are simpler to use for small projects, and typically don't have nearly as many features, eg, no graphical user interface editor.

DrJava - drjava.org

A simple, free development system. I especially like it's ability to indent the source program (select the code then hit tab). It's a single .jar file which can be run from a USB drive. This could be an important factor if you develop your programs and different machines (eg, in the student lab and at home). This is my first choice.

tIDE - snowmail.sn.funpic.de/tide/

This looks very nice, especially because it has the quality checking tools built in. Can be loaded with WebStart, or run from USB drive. However, running it is unobvious, and it isn't easy enough to recommend, yet.

JCreator - www.jcreator.com

Free LE and for pay Pro versions. I use it sometimes, and it's OK. Curiously, it's written in C++.

jGRASP - www.jgrasp.org

Many like it. The Control Structure Diagramming couild be nice, but it reformated my program in undesirable ways. Easy to install, but it rudely wants to be the default program for all kinds of files. Free. I'm not entirely enthusiastic about it, but it's popular.

BlueJ - www.bluej.org

BlueJ creates a nice development environment, which allows easy evaluation of isolated statements, inspection of classes, debugging, etc. My reaction to early versions was negative because it couldn't create "real" programs. That has changed, and hewer versions addressed most of my earlier reservations. My positive view is the result of only 30 minutes of testing, but it looked good. There is a textbook which is customized to use with it, which was very nice in many ways, but taught no GUI programming. It can also be used as a NetBeans or Eclipse plugin!

SyncJEdit - www.syncedit.com/software/jedit/

I haven't tried this, but it looks like it has some interesting features.

zBlueStudio - www.zbluesoftware.com/zbluestudio/index.cfm

Another interesting IDE that I haven't tried.

Others

There used to be many more, but keeping up with current Java releases caused many to drop out. But new good ones appear from time to time.