Evolution of EJB

The following is a view of how EJB has evolved strictly in terms of the other specifications EJB incorporates. Despite how people think of EJB, EJB is the union of all of the following APIs.

Commonly misunderstood or oversimplified, it really is the integration of many things into one place that drives EJB.

1.1 2.0 2.1 3.0 3.1
Java Transaction API (JTA)
JavaMail API
Java EE Connector Architecture
Java Messaging Service (JMS)
Java Authentication and Authorization Service (JAAS)
Java Authorization Contract for Containers (JACC)
Java Persistence API (JPA)
Java API for XML Web Services (JAX-WS)
Java API for RESTful Web Services (JAX-RS)
Java Contexts and Dependency Injection (CDI)
Bean Validation