package DataStructure; class PossibilityObject implements Comparable { double possibility; int x; int y; @Override public int compareTo(PossibilityObject comperator) { if (this == null || comperator == null) { throw new NullPointerException( "one of the Possiblity objects is null!"); } if (this.possibility > comperator.possibility) { return 1; } else if (this.possibility < comperator.possibility) { return -1; } else return 0; } }