First of all: on windows you have to restart the system after changing the environment variables (like JAVA_HOME, CLASSPATH,...). ;-) To ensure having a clean new build I deleted /work and /tmp of JBoss-server. After each reboot I rebuild and redeployed the whole project. So far I can say: _06 is working. _10 and _12 don't. I didn't test more jdk-versions. It's stupid. So be aware of the risks of changing jdk-versions without any tangible need. Never change a running system. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4071136#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...