What does JPA EntityManager.getSingleResult() return for a COUNT query?

Question

What does EntityManager.getSingleResult() return for a COUNT query?

So.. what is the precise runtime type of foo?

Object foo = em.createQuer         


        

Answer 1

Native queries can return different objects for a COUNT based on the database driver; however, all those objects extend java.lang.Number, which implements the longValue() method.

Answer 2

COUNT(t) specifically returns java.lang.Long. When its appears on its own in this context it is returned as-is.

(In other contexts the Long generated by COUNT may be wrapped, but not today.)