JEdit

jEdit is a programmer's text editor written in Java, being developed by Slava Pestov and others.
Some of jEdit's features include:

• Syntax highlighting for 70 languages
• Built-in macro language (BeanShell)
• Auto-indenting of source code
• Folding (indent and 'marker' based)
• Word wrap
• Unlimited undo/redo
• Extensible plugin architecture, with more than 50 plugins available
• Highly configurable and customizable

jEdit is released under the terms of the GNU General Public License.
There are over 50 plugins available that add powerful features and functionality to jEdit. Plugins are available to provide seemless editing over FTP, comparision or diff'ing of file versions, method completion for Java, Python scripting, XML editing, and more. Plugins can be downloaded and installed from within jEdit using the "plugin manager" feature.