code: @Override
  	public boolean isEmpty() {
  		if (getStart() == null || getEnd() == null)
  			return false;
  		if (getStart()+1 == getEnd() && !isEndInclusive() && !isStartInclusive())
  			return true;
  		return super.isEmpty();
  	}
docs: Determines if the interval is empty, meaning it contains no Integers. In
  particular, this method will return {@code true} for the open interval
  (4, 5), since there is no Integer within this interval, even though the
  start and end points are different.
  
  @return {@code true}, if the interval is empty, or {@code false} otherwise.