JTA transaction or resource-local transaction.

[Treimin Clark]

Assume the entity manager below:

@PersistenceUnit  
EntityManagerFactory emf;
EntityManager em=emf.createEntityManager();

Is this EntityManager in JTA transaction or resource-local transaction?

Please help.

[Raf Szczypiorski]

Hi. It depends on how your persistence.xml is configured - the attribute type of element persistence-context determines this. If it is omitted, it defaults to JTA in EE, and to RESOURCE_LOCAL in SE.

[Ralph Jaus]

It is an application managed entity manager. The transaction type depends on the settings in the persistence.xml file:

<persistence-unit name="PU">
<persistence-unit name="PU" transaction-type="JTA">

declare an JTA transaction entity manager (tansaction-type="JTA" is default), while

<persistence-unit name="PU" transaction-type="RESOURCE_LOCAL">

declares a resource-local transaction entity manager.

[Treimin Clark]

Thanks for Raf and Ralph

[Raf Szczypiorski]

Ralph is right, I used wrong names for the element and attribute.

[Ralph Jaus]

By the way (with fresh expressions from exam): It's good to have a clear understanding of the various types of entity managers (application managed vs. container managed, JTA vs. resource local transactions) and their persistence contexts (transaction scoped vs. extended).

[Niranjan Deshpande]

Ralph Jaus wrote:By the way (with fresh expressions from exam): It's good to have a clear understanding of the various types of entity managers (application managed vs. container managed, JTA vs. resource local transactions) and their persistence contexts (transaction scoped vs. extended).

I agree with this completely! For understanding this, I recommend PRO EJB3 Book, Chapter 5. MUST READ!