prerequisites for EJB 3

Question

Do I need hands on experience in following before starting EJB 3.

1. RMI
2. Design Patterns like facade,dependency injection
3. JPA
4. EJB 2 (I read some tutorials and observed that they all compare EJB 3 with EJB 2. So they skip basic concept of EJB.)
5. Annotations
6. Anything else, I missed

If hands on exp is required please suggest some source/tutorial for quick overview. So I can start EJB 3 asap.

• I am clear with dependency injection & facade patterns and annotations.
• I know basic of RMI. But I am not confident in them.
• I never worked with JPA.

Answer 1

Ejb2 knowledge is absolutely not required. Better yet, EJB2 knowledge isn't even recommended.

Home interfaces, Entity Beans (not to be confused with JPA entities) and portable remote objects are things that only burden you and there's no benifit to know about that in EJB3.

Best to forget EJB2 ever existed and directly learn things the EJB3 way.

RMI is also not a prerequisite. It's a special case for IFF you want to use remote beans, and even then you don't have to know a lot about RMI in order to use it.

Answer 2

Understanding annotations is definitely a must. But if you have that and basic Java programming skills, I suggest you dive right in.

• @Stateless bean tutorial
• @Stateful bean tutorial
• @Singleton bean tutorial

Seeing and running code is definitely the best way to learn.

The benefit Stackoverflow can offer increases the more specific the question gets. So at the very least, the above code could be looked at as one way to get more specific questions :)

Happy learning!