Are you doing loadtime or compile-time weaving? The version of javassist is different in 4.2.0 and 4.2.2 which probably explains the difference you are seeing when trying to upgrade the aop deployer. If doing compiletime weaving, make sure that you use the same version of AOP that ships with AS 4.2.2 to weave your code (AOP 1.5.6.GA) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4147735#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...