The Java Platform, Enterprise Edition or Java EE (formerly known as Java 2 Platform, Enterprise Edition or J2EE) has undergone several changes since Java J2EE-1.0 as well as numerous additions of new specifications.
Java J2EE 1.4, the predecessor to the Java EE 5 platform, has many powerful features than older version of Java api. Here are a few of the significant changes of Java J2EE:
Java EE 5 platform, more defaults are available, with a special emphasis on making them meaningful. Java Developers now have fewer details to remember.
The EJB software programming model is significantly simpler in Java EE 5 platform.
The new Java Persistence API is available to all Java api platform applications, including those based on Java EJB technology.