public static int hashCode(int pre,Stroke s){
  int h=(s != null ? s.hashCode() : 0);
  return 37 * pre + h;
}

public static int hashCode ( int pre , Stroke s ) { int h = ( s != null ? s . hashCode ( ) : 0 ) ; return 37 * pre + h ; }
returns a hash value based on a seed value and a stroke instance .
