hmmm... Added a cache for things created under: FileHandler.createChildHandler() So, JarHandlers would only get created once. Problem is, URLClassLoaders don't like this reuse of the JarHandler. If I remove the cache, everything boots up find, but if I add the cache, then it fails with NoClassDefFound errors with no nice stack trace I can pinpoint it to although I did see some failures in ClassLoader.declareClass. Any guesses would be appreciated. My guess is that it doesn't like how JarHandler caches the JarEntries. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3980454#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...