EJB 3.2 – an overview

Based on the Enterprise JavaBeans (EJB) specification, Enterprise JavaBeans are components that typically implement the business logic of Java Enterprise Edition applications (for Java EE, note that Oracle advises against using JEE as the acronym for Java Enterprise Edition; for more information about acronyms for Java-related technologies, visit https://java.net/projects/javaee-spec/pages/JEE). Because of their transactional nature, EJBs are also commonly used for the construction of the data access layer in many applications. However, in the newest version of the specification, container-managed transactions are no longer exclusive for Enterprise JavaBeans and can be reused in other parts of the Java EE platform.

There are basically three types of Enterprise JavaBeans:

• Session beans: This is the most commonly used EJB type. The container manages multiple instances of every class that is defined as a session bean (with an exception for singletons, which have...