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Reviewer: Arthur Gittleman

Enterprise JavaBeans (EJB) provides a technology for component transaction monitors (CTMs), which combine traditional transaction processing monitors and distributed object services. It defines a server-side component model to allow business objects to be developed and moved from one component transaction monitor to another. The developer concentrates on business logic, while the EJB-conforming CTM handles the details of transactions, persistence, concurrency, security, and making the component a distributed object. EJB competes with Microsoft technology, the most significant contrast being that Microsoft technology provides language-independence while EJB provides vendor- and platform-independence. The author notes that, while EJB makes distributed computing simpler, it is a complex technology that takes time to master. He suggests that readers be fluent in Java and have some experience developing business solutions, and he recommends appropriate resour ces for basic Java, JDBC, and Java distributed computing for those who need more background. Readers with the aforementioned background and experience will find an excellent presentation that will be extremely helpful in making the transition to EJB development. EJB is new and evolving. This books treats version 1.0. The introduction explains distributed object architectures, using example code to show how they work, and talks about component models, before describing the imaginary cruise ship business that forms the basis for the EJB code examples. The next chapter presents an architectural overview and high-level descriptions of the pieces of the EJB abstraction. The third chapter discusses the resource management facilities and the primary services available to Enterprise JavaBeans. Chapter 4 focuses on the steps needed in developing enterprise beans, first an entity bean and then a session bean. The author carefully details the steps needed but defers vendor-dependent matters such as deployment to vendor documentation. To run the examples, readers will need an EJB server, preferably one that supports entity beans, and a JDBC driver for the database used. Programs from the text are available from the publisher's Web site. After the initial example, chapters go into more depth concerning each facet of EJB. Chapter 5 discusses the client's view of an EJB system. Entity beans are used to model business concepts that can be expressed as nouns. Chapter 6 treats both container-managed and bean-managed persistence, and describes the life cycle of an entity bean. Chapter 7 contains examples of both stateless and stateful beans. A travel agent making cruise reservations, part of the continuing example, is used to illustrate transactions in chapter 8. A final chapter on design strategies treats miscellaneous issues. A useful appendix contains UML state and sequence diagrams for all bean types. The cruise ship business accessed by a travel agent serves as a nice example that allows the author to concentrate on EJB concepts while providing code to make the ideas concrete. The examples should work with any EJB-compliant server.