code: public static boolean isEqual(Object obj1, Object obj2) {
          if (obj1 != null) {
              return (obj2 != null) && obj1.equals(obj2);
          } else {
              return obj2 == null;
          }
      }
docs: Like equals, but works even if either/both are null
  
  @param obj1 object1 being compared
  @param obj2 object2 being compared
  @return true if both are non-null and obj1.equals(obj2), or true if both are null.
  otherwise return false.