The tour of the EJB component model presented here centers on several beans created and tested for a travel reservation system in a fictitious cruise ship company. The samples are just right in scale, large enough to test out key concepts in design and deployment, but small enough to be comprehensible, even to those who are not Java experts. The author pays close attention to the real-world issues of deployment with EJBs (as well as the differences among the vendor application servers that run them).

While there are enough details in Java syntax for designing both entity and session beans for the developer, sections on design here will please those who manage projects without delving much into code. Later, the author shows various ways to design entity and session beans. (For instance, entity beans can allow their bean containers to handle the details of connecting to a database, or they can do it themselves. This book demonstrates both approaches.) When it comes to session beans (which "wire" together entity beans to do real work), the author's introduction to managing state and transactions is also a standout. Tips for performance and reusability close out the book.

In all, Enterprise JavaBeans provides an engaging tour of one of the most promising component technologies. It's technically astute, but thoroughly approachable too, and can serve the needs of any manager or Java developer considering EJBs for future projects. --Richard Dragan

Topics covered: Enterprise JavaBeans (EJBs) basics, distributed architectures, Component Transaction Monitors (CTMs), bean-containers, home and remote bean interfaces, resource management, configuring EJB servers, entity beans, JNDI, container-managed and bean-managed persistence, session beans, stateless and stateful beans, transactions, design and performance hints.

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.