Question

Is there any risk to call beginTransaction on one session multiple times? I mean for example:

session.beginTransaction();
session.saveOrUpdate(object1);
// .... some works
session.beginTransaction();
session.delete(object2);
// ... some other works
session.getTransaction.commit();

I did this and it seems there is no problem (any exception or warning). In fact I want to know what happens when I use transaction in such a way.

Answer 1

The javadocs give an explanation

beginTransaction() Begin a unit of work and return the associated Transaction object. If a new underlying transaction is required, begin the transaction. Otherwise continue the new work in the context of the existing underlying transaction. The class of the returned Transaction object is determined by the property hibernate.transaction_factory.

So – it has no effect, it continues using the existing transaction. So don’t do it, as it might confuse readers (including you). You can have multiple transactions if you commit the first and then start the second.