So what we need to do is during the copying of the JBC library from 3d party dir to build, we need to do an "aopc" on the jar. But in this way, Kabir, I will need to unjar pojocache.jar first and then jar it again after instrumentation, is it correct? One other issue is for future upgrade. User can not simply drop the jar from the JBC released version. Now why can't JBoss Aop try to maintain some binary compatability between releases? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3986602#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...