It is probably working in 4.0.5 because whatever older version of the servlet classes you are picking up probably matched what is in 4.0.5. You have to find where the old servlet classes are coming from. Try this. Add '-verbose:class' to the JAVA_OPTS in the run script and run the app server again. This option causes the JVM to print out each class loaded and the JAR file it came from. You will have to redirect stdout (or is it stderr?) because this option produces a lot of output. Look for where javax.servlet.http.HttpServlet comes from. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4243794#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...