JavaBeans are pretty much just
java objects with get and set methods and a blank constructor. They are accessed only within the scope of the web server. They can be saved in and retrieved from attributes in a given scope, such as the context, session, request, and page. Tomcat supports JavaBeans.
EJB's are objects that require several files for each object to facilitate being shared between two or more computers. Tomcat does not support this at the moment, but JBoss does. JBoss includes Tomcat.