BlueJ
BlueJ is an integrated Java environment specifically designed for introductory teaching.

DrJava
DrJava is a lightweight development environment for writing Java programs. It is designed primarily for students, providing an intuitive interface and the ability to interactively evaluate Java code. It also includes powerful features for more advanced users.

Eclipse
Eclipse is a kind of universal tool platform - an open extensible IDE for anything and nothing in particular.

J
J is a text editor written entirely in Java and distributed under the GNU General Public License. It runs on Linux and Windows 95/98/NT/2000/XP.

jEdit
jEdit is a mature and well-designed programmer's text editor with 7 years of development behind it.

NetBeans
NetBeans IDE is based on an open architecture that enables you to add features to the IDE. Using the NetBeans APIs, you can create your own plug-in in modules or even develop entirely new applications that are based on the NetBeans platform.

Redwood
Redwood is a revolutionary integrated development environment (IDE) that allows programmers to visualize source code in a new way.

Source Navigator
Source-Navigator is a source code analysis tool. With it, you can edit your source code, display relationships between classes and functions and members, and display call trees. You can also build your projects, either with your own makefile, or by using Source-Navigator's build system to automatically generate a makefile.