public static int hash2(int hash,Object x,Object y){
  return 0x20000000 | (hash + 7 * System.identityHashCode(x) + 11 * System.identityHashCode(y));
}

public static int hash2 ( int hash , Object x , Object y ) { return 0x20000000 | ( hash + 7 * System . identityHashCode ( x ) + 11 * System . identityHashCode ( y ) ) ; }
utility method to combine a base hash with the identity hash of one or more objects .
