Enterprise JavaBeans

Abstract

The previous chapter showed how to implement persistent objects using JPA and how to query them with JPQL. Entities can have methods to validate their attributes, but they are not made to represent complex tasks, which often require an interaction with other components (other persistent objects, external services, etc.). The persistence layer is not the appropriate layer for business processing. Similarly, the user interface should not perform business logic, especially when there are multiple interfaces (Web, Swing, portable devices, etc.). To separate the persistence layer from the presentation layer, to implement business logic, to add transaction management and security, applications need a business layer. In Java EE, we implement this layer using Enterprise JavaBeans (EJBs).