Annotation Type NullUnknown

@Documented
@Target({FIELD,METHOD,PARAMETER,LOCAL_VARIABLE})
@Retention(CLASS)
public @interface NullUnknown

The annotated element might be null under certain defined circumstances. The necessity of the non-null check depends on situations described in the javadoc (so the non-null check is not required by default).

Consider Map.get(java.lang.Object) as an example of such a method - depending on usage of the Map null may be legal or forbidden.