I am having a difficult time figuring out the cause of this. I recently installed jboss 4.2.1.GA jdk 1.5.0_11 on linux. We have 3 servers running 4.0.5.GA and now 3 new servers with 4.2.1.GA. Only on the 4.2.1.GA servers after an hour of web traffic, the java CPU utilization in top shows 99.9% and JBoss tomcat :8080 and :8009 ports are not responsive. Once in this state I cannot run the listThreadCpuUtilization MBean operation to see what thread is taking up the most cpu. I have attached jmap and jstack outputs to this post. Can you help me figure out what thread might be the source of the problem? Is it normal to see so many threads state = BLOCKED? Any ideas? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4088602#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...