public boolean equals(Object interval){
  if (intervals == null) {
    return false;
  }
  return intervals.contains(interval);
}

public boolean equals ( Object interval ) { if ( intervals == null ) { return false ; } return intervals . contains ( interval ) ; }
determine the matching test . defaults to equality of the node based upon the interval . subclasses can override , for example , to determine if the interval is contained within the node ' s information .
