code: private static final boolean match(Object obj1, Object obj2) {
          return obj1 == obj2 || (obj1 != null && obj1.equals(obj2));
      }
docs: Determine if two objects, either of which may be null, are equal.
  
  @param obj1
  one object.
  @param obj2
  another object.
  
  @return true if the objects are equal or are both null, otherwise false.