An addition to the EJB component model version 2.0 is "message-driven beans." These are enterprise beans that allow J2EE applications to process messages asynchronously. What are some of the uses of such a component? What sort of new enterprise architecture possibilities do message-driven beans open up?
The J2EE/EJB specification uses many techniques that are actually just implementations of the "use an intermediary" tactic. Find as many distinct realizations of these instances as you can.
Consider the CelsiusTech case study presented in Chapter 15. Would J2EE/EJB be a good infrastructure choice for implementing this system? Justify your answer.