Difference between J2EE design patterns and Patterns of Enterprise application architecture

I am trying to enhance my knowledge in "design" aspects of Software (engineering), and I am more into Java world.

The first thing I came across was GoF book, which as per my understanding is the "core" or "foundation" design patterns (please correct if i am wrong in interpreting it).

I came across the following terms as i try to go in depth for getting the knowledge of design (patterns).

1) J2EE design pattern.
2) Patterns of Enterprise application architecture.
3) GoF patterns.

I am bit confused as to why there are many design patters and which is used when? In particular, what is the difference between the patterns in #1 and #2?

Any explanation in simple words would be of great help.