Question

I am investigating a connection leak in my code. We are using c3p0 to manage the connection pool and my general Hibernate use pattern is something like this:

EntityManager entityManager = entityManagerFactory.createEntityManager();

try {

    EntityTransaction transaction = entityManager.getTransaction();
    transaction.begin();

    //..Work involving calls to find() and merge()

    transaction.commit();

} catch (... e) {
   //..log message, throw nicer exceptions

} finally {
   entityManager.close();
}

Does this code have the potential to leak DB connections? Do I have to explicitly rollback a transaction in the case of a failure, or is that done automatically? Does entityManager.close() ensure that DB connections are returned into the connection pool?

Answer 1

Use transaction.rollback() in all your catch blocks.
The transaction will be closed without a commit then