Hello,

We are currently designing the Transaction and Concurrency Handling of our application and have a few questions concerning Hibernate Transaction and Session Handling. We have read all the documentation about Transactions and Concurrency and have a few questions:

We are generally talking about Hibernate 3.2 (EJB3.0) and J2SE.

- We have a EntityManagerFactory which holds a Connection Pool for our Database.

- If we need a Persistent Context, we fetch an EntityManager from our EntityManagerFactory. This means, simple expressed, we get a connection to our database from our connection pool.

- We want to do something. For this we open a transaction for the current EntityManager with EntityManager.getTransaction(). Now we have an open transaction. We have always only one opened transaction for one EntityManager.

- If we close the Transaction and the EntityManager, the connection is returned to our connection pool to make it available for the next EntityManager.

Could someone please confirm the above described procedure? It is very essential for me to understand the concepts of Hibernate's Transaction Handling.

Regards,

Christoph.[/b]

The connection is not retrieved until the EM actually needs it, this is not at EM creation time.
you can have multiple resource-local Tx per EM, but only one at the same time
When the tx is commited or orllbacked, the connection is released.


But once again, JTA/EJB 3 is a nicer concept and works on SE

does that mean the connection is put back to the connection pool or is the connection closed? I am very petty because creating db-connections is very expensive.

thx.
chistoph.

It's not. That's why you have a connection pool.

JTA really works in a J2SE environment? I think it would be the best solution to use JTA, but I can't find good documentation on it.

It is activated with the hibernate.transaction.factory_class property. But I can't find any docu how to use it, perhaps someone has good resources about using JTA with J2SE.

Regards,

Christoph

Isn't JTA and JNDI available without Embedded EJB3 for J2SE?

When I set

and I make a new EntityManagerFactory

I get a NoInitialContextException. Should it run on a J2SE or really do I need Embedded EJB3?

Regards.