Caret operator (^) produces this hint inappropriately:        


1        private boolean testBug(Object o1, Object o2) {
2            if ((o1 == null ^ o2 == null) || o1 != null) {
3                return true;
4            }
5            return false;
6        }

On line 2 "o1 != null" is highlighted with "Unecessary test for null - expression is never null". The first part of the test returns true if exactly one of o1 or o2 is null, therefore o1 can be null.