Currently, AnnotationLiteral.hashCode() always returns 0 if there are no members (ignoring annotation type completely). Although it does not break Object.hashCode() contract, I believe we should either return a number based on the annotation type (to make the annotation literal instances more usable in hash tables) or simply return zero and don't cache the value at all.

UPDATE: We may not return a number based on the annotation type because it would break the java.lang.annotation.Annotation.hashCode() contract.