If you were ever looking for a summary of each version of the J2EE Spec, it can take a few minutes to find it. So, here is a summary. The J2EE Specification is actually collection of numerous different Java-based technology specifications.
A summary of the J2EE family of specs can be found here.
Starting with this release, the Specification name was officially changed to Java Enterprise Edition-JEE. A summary of the JEE family of specs can be found here.
A summary of the JEE spec can be found here.