"alesj" wrote : "adrian(a)jboss.org" wrote : So we are obviously tickling something inefficent | | in JDK5 that has been fixed in JDK6? | How to find this needle in JDK haystack? :-) I still see the two biggest hits as the VFS and aop pointcut matching when I've measured it. So for the VFS, I guess it would be that JDK6 no longer uses memory mapped files for jars. For the AOP pointcut matching it would be the reflection calls. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4193079#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...