Well, turning the blacklist off altogether is one way to fix it. :-) But it is inconsistent. If you had three levels of hierarchical domain it still wouldn't work because loadClass(...) still checks the blacklist. The issue is that the blacklist is being checked before the parent (cache) is asked wether it knows the class. The order should be more like: 1) Check the current domain to see if cached == false 2) Check the parent domain to see if cached == true 3) Check the current domain to see if blacklisted == true Currently (2) and (3) are the wrong way around. Your fix just removes (3) In fact, the real issue is that (2) is not happening at all except inside the classloader lock which is not very efficient. I'll fix it properly, but it is slightly complicated in that step (2) isn't the correct thing to do if the class doesn't match the parent filter. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4228564#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...