The hibernate query.list () method returns an empty list instead of a null value

Question

If there are no rows, then both query.list () and criteria.list () return an empty list instead of a null value. What is the reason for this?

Answer 1

The reason is not to force null checks into client code, according to Effective Java 2nd Edition , Paragraph 43: Returning arrays or collections empty, not zeros .

This makes client code simpler and less error prone (and, most likely, also a method implementation).

The zero-return idiom is probably a delay from the C programming language; the length of the arrays is returned separately from the real arrays. In C there is no advantage in allocating an array if zero is returned as length.

Answer 2

It is consistent: the list is returned with all the results, whether they are or not.