The Enterprise JavaBeans[tm] Tier

In a multitier J2EE application, the Enterprise JavaBeans^TM (EJB^TM) tier hosts application-specific business logic and system-level services such as transaction management, concurrency control, and security. Enterprise JavaBeans technology provides a distributed component model that enables developers to focus on solving business problems while relying on the J2EE platform to handle complex system-level issues. This separation of concerns allows rapid development of scalable, accessible, and highly secure applications. In the J2EE programming model, EJB components are a fundamental link between presentation components hosted by the Web tier and business-critical data and systems maintained in the enterprise information system tier.

This chapter examines the nature of business logic and describes the problems a developer needs to resolve when implementing business logic. It then describes the component model that the EJB tier of the J2EE platform provides to address these problems. The chapter then presents recommendations and practices to best utilize the services provided by the J2EE platform.

In this chapter:

• Business Logic
• Enterprise Beans as J2EE Business Objects
• Entity Beans
• Session Beans
• Design Guidelines
• Summary
• Questions and Answers