Hi!

I use Hibernate version 3.2.0cr2.

Can it happen that the uniqueResult() method returns null in the following code ?



If the criteria matches zero rows, then after the projection it should return an Integer value of zero, right ?

I ask because in some cases it returns null (and by that causes a null pointer exception) in our application.

Thanks and regards,
David

The only relevant doc I could find was JSR-220-persistence and in section 4.8.4 it says that for COUNT the return type is Long and in case of no objects it returns zero.

That does not match our case (return type is Integer and it sometimes returns null) :-(

Can anyone sched some light on this ?

ah, found it.

We use two (and more...) session factory's.
Due to some changes in some related code the factories get mixed up.
So class C was mapped in factory 1 , but not in factory 2.
Factory 1 should be used, but in some cases we used factory 2 by mistake.

For get() methods it throwed "MappingException: Unknown entity C",
but createCriteria(C.class).list() just returns null, no exception.
Same if we add a projection to it.