Some people will argue that it’s not worthy comparing Tomcat and JBoss, because one of them is a superset of the other. In fact JBoss is bundled with a forked version of Tomcat. So JBoss is Tomcat plus:

* JMS messaging provider

* Web Services engine (JAX-WS and/or JAX-RS)

* Management capabilities like JMX and a scripted administration interface

* A powerful data grid solution (Infinispan)

* Advanced security, e.g. out-of-the-box integration with 3rd party directories

* A dynamic and powerful clustering engine

* Transaction management service

Still many decision makers have to choose between these two, so lets’ take a deeper look at them.

via JBoss vs Tomcat « Altabel Group's Blog.