Tomcat is just a servlet container, i.e. it implements only the servlets and JSP specification. Glassfish and JBoss are full Java EE servers (including stuff like EJB, JMS, ...), with Glassfish being the reference implementation of the latest Java EE 6 stack, but JBoss in 2010 was not fully supporting it yet.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…