Summary

Another long day, but you now have lots of good new material under your belt. You've learned that Entity beans represent persistent domain data with corresponding domain (not application) logic. You've seen that the constituent parts of Entity beans are pretty much the same as Session beans, though Entity beans also require a primary key class that must be custom-developed if the key is composite.

You've also learned that there are two different ways to implement Entity beans, either using bean-managed persistence, whereby the persistence code (JDBC, for example) resides within the bean code, or using container-managed persistence. You now know the lifecycle for BMP beans and how to implement such beans.

You saw that the EJB specification allows local interfaces to be defined for EJBs, as well as or instead of remote interfaces, and saw several good reasons why Entity beans should always use local interfaces.

Onto deployment, you now know that the J2EE RI allows EJBs can be deployed using a command line interface. A deeper understanding of the XML deployment descriptor is needed, but the process for deployment is (arguably) more portable and faster.

Finally, you've learned numerous design techniques, patterns, and idioms that should set you up for designing and implementing Entity beans effectively.