J2EP is a reverse proxy running on a J2EE engine. The proxy is written in java and was originally designed with Tomcat in mind, but any engine should work fine. A set of basic mapping rules are included but they can easily be extended to your own needs.
Oroena is a fully Java 2 Enterprise Edition powered Open Source Reverse Proxy engine. It provides unique session, security or server access management for a multi-server architectured portal.