You can find the full source code for this website in the Seam package in the directory /examples/wiki. It is licensed under the LGPL.
Seam does not work with JDK 1.4 and requires JDK 5 or above as it uses annotations and other JDK 5.0 features. Seam has been thoroughly tested using Sun's JDKs. However there are no known issues specific to Seam with other JDK's.
For some JDK6 specific considerations please see Does Seam Work with JDK60