I went through your first post once again and was a bit confused by the statement: anonymous wrote : When I startup my JBoss, I don't know why the web application uses the ClassA in the mdb.jar which has no system out Can you explain as to who is invoking this ClassA? Is it JBoss or it from some other class? Just trying to understand as to why JBoss would invoke that class when deployment is going on, assuming ClassA is just a POJO class(or is it not?) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3957696#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...