以下是中的哈希函數的源代碼java.util.HashMap。這些評論很好地解釋了它的成就。但是如何？-什么是^和>>>運營商在做什么？有人可以解釋的代碼實際上是如何做的評論有什么說的？/** * Applies a supplemental hash function to a given hashCode, which * defends against poor quality hash functions.  This is critical * because HashMap uses power-of-two length hash tables, that * otherwise encounter collisions for hashCodes that do not differ * in lower bits. Note: Null keys always map to hash 0, thus index 0. */static int hash(int h) {    // This function ensures that hashCodes that differ only by    // constant multiples at each bit position have a bounded    // number of collisions (approximately 8 at default load factor).    h ^= (h >>> 20) ^ (h >>> 12);    return h ^ (h >>> 7) ^ (h >>> 4);}