Open Source Related Forums at Your Favorite Things:
Computers and Internet - Discussions pertaining to hardware, software, internet, web design, internet, programming and more.
Programming - C, C++, PHP, Perl, Delphi, Visual Basic, etc.. If you are seeking out a discussion on computer programming, then this is your place to be.
Ginipad - Integrated Development Environment for Java, written in Java itself. It provides syntax highlight, automatic code completition, edit-compile-execute cycle. It require JDK 1.4. [Open source]
Gwydion Sheets - Gwydion Project's hypercode programming environment for Java supports complex hypertext interlinking, multiple groupings of code, and searching of code and documentation fragments. [Open Source, Public Domain]
jEdit - Programmer's text editor; includes support for dynamic download and installation of new plugins from a central plug in server. Java, XML and JSP source are well supported.
Red Hat Source-Navigator - 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. [Open Source]
Schmortopf - A freeware Java IDE. Source available too.