BlueJ
An integrated, interactive Java development environment, featuring class structure diagrams, interactive invocation and an easy-to-use interface. BlueJ was developed for teaching and learning Java. [Freeware]
JADE
Model-based application development supported by a Java based Application Design Tool as well as a lightweight Java Integrated Development Environment. [Freeware]
JavaTools
A simple IDE that helps create, and manage Java applications and applets.
jGRASP
A multi-platform, multi-language IDE that adds Control Structure Diagrams to Java, C, C++, Objective-C, Ada, and VHDL source code. [Freeware]
QuickCup
A project-based IDE is easy to pick up, giving one-click compile, run (as application or applet), package (into JAR files), and upload to web site. Text editor is no-frills but functional. On-line help.
SyncJEdit
A free Java IDE with integreted tools: class hierarchy, add listener automatically, project relationship, view zipped file, add class code, runtime input stream, view class and Java file in class paths, format Java file.