When using generic Lists, I get compiler warnings. If I want to have a generic return type, which of the following two options should be done? (Note the use of a cast in the second option.)

Also, what's the disadvantage to not using @SuppressWarnings? It seems like it's optional...

@DataModel
 @SuppressWarnings("unchecked")
 public List<Something> getSomethings() {
 return myQuery.getResultList();
 }

Without @SuppressWarnings, the above gives the warning:

Type safety: The expression of type List needs unchecked conversion to conform to List<Something>

@DataModel
 @SuppressWarnings("unchecked")
 public List<Something> getSomethings() {
 return (List<Something>) myQuery.getResultList();
 }

Without @SuppressWarnings, the above gives the warning:

Type safety: The cast from List to List<Something> is actually checking against the erased type List

Why is this error showing up in the second case. If I'm casting, shouldn't I be able to leave off @SuppressWarnings with no problem?