I am new to hibernate but have been helping someone debug an issue they were having.

In the code they were getting the hibernate connection to reuse it outside of the hibernate transaction like this:



Now the problem here is obviously that the connection shouldn't be being reused and closed like this. However, when the session is closed and a subsequent call to SessionFactory.OpenSession() is made the session it returns generates errors because the connection is closed.

It was my understanding that when calling openSession() from a SessionFactory it got a new connection.

Can someone explain how the SessionFactory is actually handling the connections?

There is nothing in hibernate.cfg.xml that specifies any kind of connection pooling.

Thanks in advance,

Ian

The creation of connections is managed in "the environment" in which your Hibernate application runs.
There can be a great variety of environments:
a simple Java client application, a Hibernate/Spring application running under a web server, a JPA or EJB application running on an application server, etc.

Evidently in your case, "the environment" was counting on that particular connection to continue existing. Thus, your assumption that one fresh connection is created every time a session is obtained is wrong. (It would be very expensive, resource-wise).

You should try not to acquire connections in that fashion, and you should most certainly never close the connections acquired in that way, because you would be making your Hibernate code assume a responsibility (managing connection state) that is not his.

I understand that this is a bad thing to do and should never be done...I was fixing someone elses code where this was the issue.

The is a stand alone java app that doesnt use any external connection pool and so hibernate handles making the connection.

I'm simply trying to understand how the connections are handled as the API seems to be misleading.

From the hibernate API:



This would seem to imply that if i call openSession a database connection is created. If this was the case and a connection is being "created" I wouldnt expect to see that the connection is closed.

This being misleading I just want to understand how this actually works for my own learning benefit

A connection is not created.
The obtained connection should not be closed.