User talk:Elayarajasubbaiah

What is new in EJB 3.0
The major differences i have seen between EJB 2.x and EJB 3.0 versions are as follows :-

1). Removal of home interface enabled simple lookup process in ejb 3.0

2). EJB deployment descriptors are not required in ejb3.0

3). Annotations are used in ejb3.0

4). EJB 3.0 entity beans don’t have home and remote interfaces.

5). EJB 3.0 entity beans/JPA becomes local. Remote annotations are not at all supported for entity beans.

6). EJB 3.0 beans don’t implement the standard interfaces like javax.ejb.SessionBean and hence no need to implement the container call back methods like ejbActivate, etc

7). Query is very flexible. Multiple levels of joins are enabled through the refined EJB-QL

8). Can be used with pluggable, third party persistence providers

9). Security can be provided either through annotations or through deployment descriptors

10). POJO like EJB 3.0 entities become lightweight and easy to convert from a DAO to Entity bean or vice versa. Since EJB 3 entities don’t need implement any interface.

I need more info on the following factors :-

1). Performance efficiency achieved by the removal of home interface, deployment descriptor, etc

2). container call back methods like ejbCreate etc are eliminated. Then what about the customised implementation possibility of session bean in ejb3.0?

3). Is all the transaction attributes in ejb 3.0 are supported in ejb2.1?

4). REQUIRED - Start a new transaction if necessary

SUPPORTS - Don’t start a new transaction, but use one if exists REQUIRESNEW – Always start a new transaction, suspending the old one MANDATORY - Require the caller to have started a transaction NEVER - Forbid the caller to have started a transaction NOTSUPPORTED – Suspend any active transaction