question: public static int hash4 ( int hash , Object x , Object y , Object z , Object w ) { return 0x40000000 | ( hash + 7 * System . identityHashCode ( x ) + 11 * System . identityHashCode ( y ) + 13 * System . identityHashCode ( z ) + 17 * System . identityHashCode ( w ) ) ; }
target:  Utility method to combine a base hash with the identity hash of one or more objects.