How does EJB 3.0 improve over EJB 2.1?
The goal of EJB 3.0 is to target ease of development, the main theme of the Java EE 5 platform release. EJB 3.0 is a major simplification over the APIs defined by the EJB 2.1 and earlier specifications. The simplified EJB 3.0 API allows developers to program EJB components as ordinary Java objects with ordinary Java business interfaces rather than as heavy weight components. Both component and client code are simplified, and the same tasks can be accomplished in a simpler way, with fewer lines of code. Because it is much simpler, EJB 3.0 is also much faster to learn to use than EJB 2.1.