Rob Castaneda & Stefan Denninger 
Enterprise JavaBeans 2.1 [PDF ebook] 

Enterprise Java Beans (EJB) is a server-side component model for transaction-aware distributed enterprise applications, written in the Java programming language. Enterprise Java Beans 2.1 details the architecture of the Enterprise Java Beans component model. After the authors introduce the component paradigm, they move on to cover EJB architecture basics. Building on the foundation formed in those introductory topics, they discuss the different component types (session-, entity-, and message-driven beans) in detail. This is followed by a comprehensive introduction to the Java Message Service (JMS), so you understand the ideas behind asynchronous and parallel processing provided through message-driven beans. Transactions, security, and the newly introduced timer service round out the book.This invaluable resource also discusses topics beyond the specification: inheritance, coupling of EJB components, quality assurance, and more. After reading this book, you’ll understand the benefits and the limits of EJB and have the knowledge necessary to turn business requirements into EJB-based applications.