Tomcat is a "servlet container". That is, it will run servlets and JSPs. In addition is server static web content. JBossAS is a Java EE application server. It need to not only provide a servlet container (which it uses Tomcat to provide), but must also serve EJBs, messaging services, and a whole host of other services. That is the basic difference. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4170813#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...