Book excerpt: Includes more than 30 percent revised material and five new chapters, covering the new 2.1 features such as EJB Timer Service and JMS as well as the latest open source Java solutions The book was developed as part of TheServerSide.com online EJB community, ensuring a built-in audience Demonstrates how to build an EJB system, program with EJB, adopt best practices, and harness advanced EJB concepts and techniques, including transactions, persistence, clustering, integration, and performance optimization Offers practical guidance on when not to use EJB and how to use simpler, less costly open source technologies in place of or in conjunction with EJB