I have heard/read bad things about EJB 2.0 ... and I guess nowdays most developers won't recommond and companies won't approve EJB 2.0 project.
So do we need to know how to implement EJB 2.0? Of course we need to understand the underlying concept of EJB. Can we go straight study the EJB 3.0 with a blind knowledge of EJB 2.0??
actually no EJB 2 knowledge is required to program in EJB 3. With EJB 3 being POJOs, every Java developer can become an EJB 3 developer very easily. For our book, EJB 3 In Action, we do not assume that you know EJB 2.