Hello All:

We have an Application that runs within the Tomcat container. The persistence layer is coded using JDBC.

I have been looking into Hibernate and of course and very impressed. I would want us to move our persistence layer to use Hibernate.

However I do not see getting permission to change the entire existing JDBC code to Hibernate. Not at one shot. There is just too much of it. I do see the opportunity to use Hibernate in the new features we plan to add. Hopefully we will be able to move the persistence layer to completely use Hibernate over time.

The questions I have are;
- Can Hibernate co-exists with existing JDBC code?
- Has anyone tried this configuration? Please share your experience
- Is there a set of guidelines to be followed to achieve this?

Looking foward to your feedback and comments. Thank you.

Gowtham.

It depends, but mostly yes.
Hibernate coexist pretty well with concurrent access to DB (even from non Java world).
Hibernate allows you to give to it the underlying JDBC connection.
Hibernate allows you to access the underlying JDBC connection.
Thus concurrent modification within the same Tx is pretty easy.

But:
Hibernate use at least 1 level of cache (the session one). So changing an object on Hibernate and at the same time sneakily modify the associated row using the same connection will lead to strange behavior. Otherwise Tx demarcation will protect you pretty well.

Thank you for the advise. Will try it out and if successful will update the board.