Unless you're switching to Hibernate or some other technology, its not useless. A lot of the basic principals, especially with session and message driven beans are the same. The entity is the major throw away part, although if you're in the EJB3 world its good to know the background of EJB2, especially if you have to face it at some point.
Bupjae, I wouldn't recommend buying the Head First book at this point. if you already own it, the book is still worth reading for concepts. You just have to remember that the details (syntax) doesn't apply anymore and skip the entity bean parts. Also, don't focus too much on the certification questions as you wouldn't be taking an EJB 2 exam.
Originally posted by Bupjae Lee: I think there were not many differences in basic concepts for session and message beans.
But, I think entity bean was changed completely, and need some research(?).
Session beans and message driven beans had some syntax changes, but all the concepts stayed the same. You are correct that entity beans changed completely.
> PS1) The word "googled" is against UseRealWords rule? Googled shouldn't be against the rule. It let me post it. Were you using a different spelling of it perhaps?
> PS2) Is there free web hosting site supporting EJB? I don't of any. Mycgiserver.com used to but I think they went out of business. You can install JBoss on your own machine for learning though. You just wouldn't be able to host for free.
> PS3) Why entity bean changed completely? Scott (the moderator of this forum) actually wrote a blog entry about this recently.
[edited to state it let me post googled] [ August 30, 2008: Message edited by: Jeanne Boyarsky ]
Joined: May 14, 2007
When I read Head First EJB, it was said that "EJB 2.0 CMP is better 1,000,000 times than EJB 1.1" (about p.305? - My mother language is not English so I have translated book) so I thought everyone was happy with EJB 2.0 CMP.
However, after I read the doom of EJB2 CMP today, I understand that my first thought was wrong and why entity beans are changed completely.
When I googled for EJB3 first time, the word "Hibernate" came out often, but I didn't know what and why. Now, I understand what is Hibernate.
Can I think that "de facto standard" finally become "standard" for EJB3? [ August 30, 2008: Message edited by: Bupjae Lee ]