Apache NetBeans
Modernized fork of NEdit, with unicode support and AA text rendering
Kile is a feature-rich LaTeX editor
Jexer - Java Text User Interface Library
A powerful editor and graphical debugger for code written in Scilab
A hackable text editor for the 21st Century
Web IDE in single HTML file
A syntax highlighting, code folding text component written in Swing
A modern, lightweight yet powerful text editor
CodeLite: an open source, cross platform C/C++/PHP and JavaScript IDE
A lightweight programming environment for Java
Vim-like editing in Eclipse
Electronic design and programming tools suite like Eagle, MpLab
Develop AMX NetLinx projects in the Sublime Text editor.
Develop Crestron Simpl+ modules in Sublime Text.
Turn gVim into a Crestron SIMPL+ IDE.
PHP Support for GNU Emacs
Graph algorithms interpreter, IDE, debugger, 3D visualizations.
JetBrains Meta programming System