code: private boolean equalByComparator(Object o1, Object o2) {
  		return comparator == null ? o1.equals(o2) : comparator.compare(o1, o2) == 0;
  	}
docs: Using the configured comparator (or equals if not configured), determine
  if two objects are equal.
  
  @param o1 Object to compare
  @param o2 Object to compare
  @return boolean true if objects are equal