Enterprise JavaBeans (EJB) technology is the server-side component architecture for Java Platform, Enterprise Edition (Java EE). EJB technology enables rapid and simplified development of distributed, transactional, secure and portable applications based on Java technology.
EJB 3.0 was introduced with Java EE 5 in 2006. At the time, it greatly simplified development by introducing the use of Java annotations, by making XML deployment descriptors optional and by adopting a convention-over-configuration approach. It also included the Java Persistence API for persistence and object/relational mapping with Java EE and Java SE which has since become an independent JSR of its own.
EJB 3.1 (part of Java EE 6 and released in 2009) introduces a multitude of new features including :