# Understanding JSR220: EJB 3.0

The Java 2 Enterprise Edition(J2EE) Enterprise JavaBeans (EJB) are a component architecture that you use to develop and deploy object-oriented, distributed, enterprise-scale applications. An application written according to the Enterprise JavaBeans architecture is scalable, transactional, and secure.

The purpose of EJB 3.0 (JSR220) improves the EJB architecture by reducing its complexity through the use of metadata (annotations) and specifying programmatic defaults of that metadata.

Adding persistence to a Java project
Mapping an entity