I am planning to learn EJB from scratch eventhough I know (not thoroughly) about the 3 types of beans, CMP, BMP etc in EJB2.0.
My question is , is it possible to start learning EJB3.0 right away or do I need EJB2.0 knowledge as a pre requisite? I am looking for the best option.
Girish B
SCJA 1.0 (86%)
SCJP 1.4 (91%)
OCPJWCD (86%)
A lot of people will tell you that EJB2 is a waste of time but I tend to disagree. Chances are you may encounter EJB2 'in the wild' so better to learn about both, starting with EJB2. That way when you get to EJB3 you'll appreciate the simplicity of it a lot more
I learned EJB2 with Head First, and now I'm learning EJB3 with other resources.
I think that, except Entity bean, the basic concept regarding EJB is same between EJB2 and EJB3. Changes like using annotation or disappearing home interface are some minor part.
However, Entity is completely different between EJB2 and EJB3.
My opinion is that maybe learning EJB2 is not necessary but it is not waste of time. You can start with EJB3 and later you may learn EJB2, or vice versa.
You can read the first few chapters of Head First EJB(2.0) to get the core concepts of ejb's, mainly chapters related to Session Beans and Message Driven Beans. You can skip the Entitiy Beans part.
Once you have the basic idea of ejb 2.0, you can pickup any EJB 3, you will appreciate the new featurs and also easy to understand.
Please directly start with EJB3.0 , it is very simple ,nice interesting. If you read EJB2.0 i am damn sure you will never try to learn EJB . EJB2.0 is very complex espcially HeadFirst series.
I started with EJB 2 three years ago (actually I am still engaged in an EJB2 project, arg!!). When I got started in EJB3 was fantastic. Basically the concepts are the same (exception Entity Beans) and because of this I advice you to start on EJB3 directly. Do not worry about EJB2 anymore, except if you need it in your job. With EJB 3 you'll learn all the concepts in an easy way (and more fun).
Regards, Jair Rillo Junior
http://www.jairrillo.com/blog, SCJA 1.0, SCJP 1.4, SCWCD 1.4, SCBCD 5.0, IBM SOA Associate (Test 664).