Hi, we have (I guess) the same problem on our JBoss (3.2.7). We tracked down a first memory leak some time ago (in Xalan 2.7) but our server still crashed out of memory. Today I analyzed a second memory dump and found out, that we had sessions in memory that were older than a week. The stats-servlet told me, there were 1500 sessions created, 770 expired, 100 active. My logfiles told me, that 600 sessions were destroyed. Thirty sessions lost - in one day. Searching the web I finally got to this page. http://issues.apache.org/bugzilla/show_bug.cgi?id=37356 I think this matches exactly my problem (we are running a two-cpu-machine with hyperthreading). Think this might also what troubles you. (Well, take a close look at post 48...) Hope there will an official patch soon... View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3973220#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...