RSyntaxTextArea is a syntax highlighting text
editor. It has support for over 20 programming
languages and is completely customizable. By
extending JTextComponent, it easily integrates
into any Swing application and provides an easy
way to add syntax highlighting to a program.
RText is a fully customizable programmer's text
editor. Some of its features include syntax
highlighting, editing multiple documents at once,
printing and print preview, find/replace/find in
files dialogs, undo/redo, and online help.