RSyntaxTextArea is a syntax highlighting, code folding text editor. It has support for over 30 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.

Changes:
This release improves syntax highlighting of Web languages (HTML, JS, PHP, and JSP), improves rendering performance, and fixes a few bugs.

URL:
RSyntaxTextArea – Freecode