The new version of container-managed persistence (CMP) beans in 2.0 is more portable and robust than in the older 1.1 version. Most significant is the introduction of the relationship fields, which allow entity beans to declare relationships with each other as natural references. In order to make this huge leap in component relationships possible, EJB 2.0 had to redesign how entity beans are defined and interact. Our new 3rd edition examines this critical CMP model in detail.
Local interfaces are thoroughly discussed as well. Local interfaces allow beans that are co-located to interact without the overhead of remote method calls. This improves the performance of beans considerably and complements the CMP relationship fields.
Message driven beans are a new kind of enterprise bean based on asynchronous messaging and the Java Message service (JMS). Instead of responding to Java RMI calls, message driven beans process JMS messages sent by messaging clients. An entire chapter is devoted to message-driven beans and how to use them effectively.
In addition, the 3rd edition contains an architecture overview, information on resource management and primary services, design strategies, and XML deployment descriptors....Continua
Ok, let me start by saying that the author of this book is indeed well prepared and able to go into detail in his explanations. If you are really interested in programming with EJB this is one of the books you should check, despite its many flaws.. The first three chapter make
a fully successful attempt to protect the mysteries of J2EE from
profane eyes by putting a deep sleep spell on the reader.
If you survive it you will probably find yourself wondering about the order in which the story is told...
First a hurried example involving a session bean collaborating with an entity bean, then one chapter on the client side (which of course you need to understand how the heck you could have tested the beans just developed), then entity beans get presented again but this time in more detail.. only you get to know first the CMP flavour (which is the more complicated) and the BMP flavour after, totally against what common sense would advice. Then you go into session beans, which , being simpler than entities should have been presented before..and how about a chapter 16 on deployment descriptors? They are the configuration files you need to deploy ANY EJB and you explain them at the end of the book? The impression is this author would be much better if he stopped thinking by compartments
and trying to make things appear much more difficult and deep than what they actually are. Also, the workbooks with the exercises for this text are a joke. You will be presented with
canned code and a few ant scripts to execute, compile, build
deploy and run the code. Very kewl but if you know what you are doing you can do it yourself and if you don't .. well clicking on a few batch files or executing ant scipts won't teach you much I can assure you..