If this doesn't come with your Java VM, then you can get them from Sun's Java web-site . To build the source, you will need Ant from the Apache Jakarta project. This will probably be inspired by the use of Jakarta-Tomcat 4.0. Overhaul of HttpAdminable. While it will always remain optional to use this, perhaps it makes more sense to rewrite the way it is done.
Current possibilities are to use Jakarta-Struts as the frame work.