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How to Catch Exception

dinesh thalis
Ranch Hand

Joined: Nov 19, 2008
Posts: 39
I'm using EJB3. As usual, i'll use the EntityManager's API to do CRUD operation, such as, em.persist(), em.merge() etc.

So now I want to catch exception while performing em.persist() and do my own thing.

If I used @TransactionManagement(TransactionManagementType.BEAN) I can handle exception below show my code.




Problem is if I use @TransactionManagement(TransactionManagementType.CONTAINER) I can't catch exception, I used same code( display above), how can I overcome this problem.

If you can provide more details about exception handling in EJB3( reference link) it's more helpful to me.
Rodrigo Lazoti
Greenhorn

Joined: Mar 13, 2009
Posts: 9
You can handle/catch exceptions in BMT or CMT Enterprise Beans.
See the links below more about transactions and handling of exceptions:

http://java.sun.com/javaee/5/docs/tutorial/doc/bncih.html
http://java.sun.com/javaee/5/docs/tutorial/doc/bnbpj.html

And I recommend you check the specs:

http://jcp.org/aboutJava/communityprocess/final/jsr244/index.html


Best Regards!


Rodrigo Lazoti.
blog: http://www.rodrigolazoti.com.br
Rodrigo Lazoti
Greenhorn

Joined: Mar 13, 2009
Posts: 9
duplicate message. sorry...
Yair Ivan
Greenhorn

Joined: Jul 13, 2008
Posts: 15

Hi.


Thanks Rodrigo for information.

I add the following items:

- In EJB 3 in Action section 6.2.5 Transaction and exception handling.
- In Entreprise JavaBeans 3.0 (O┬┤Relly) Section 16.6 Exceptions and Transactions.

By.


SCJP 6.0, SCBCD 5.0, SCDJWS 5.0
dinesh thalis
Ranch Hand

Joined: Nov 19, 2008
Posts: 39
I read this tutorials but still I'm fail



I'm using container manager transaction and persist account details. if some body try to persist incorrect account information I want to give customer exception(message) instead of system generated message. Above code show that but this not work. please help me how to it?
Jaikiran Pai
Marshal

Joined: Jul 20, 2005
Posts: 10207
    
166

With CMT, the actual queries are fired on transaction completion, i.e. after the method exits. So the catch block will never be able to catch such exceptions which happen within a transaction synchronization callback. You'll see the difference if you add a em.flush after the em.persist. That way, the queries will be fired immediately instead of waiting for tx synchronization:



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dinesh thalis
Ranch Hand

Joined: Nov 19, 2008
Posts: 39
Below show how I try to handle this issue. Is it write or wrong. Using this way I can succeed some extend, Is there any suggestion regarding this.

 
It is sorta covered in the JavaRanch Style Guide.
 
subject: How to Catch Exception