JOnAS is a leading edge Open Source implementation by OW2 of the Java EE specification.
The stable versions are J2EE 1.4 certified. The License used by JOnAS is the LGPL.

http://wiki.jonas.objectweb.org/xwiki/bin/download/Main/Overview/jonas-5-schema.png

It uses OsGi as its core.

Wiki Site: http://wiki.jonas.objectweb.org/xwiki/bin/view/Main/WebHome