深入浅析Java中HashMap与HashTable容器的区别

 public V put(K key, V value) {  if (table == EMPTY_TABLE) {   inflateTable(threshold);  }  if (key == null)   return putForNullKey(value);  int hash = hash(key);  int i = indexFor(hash, table.length);  for (Entry<K,V> e = table[i]; e != null; e = e.next) {   Object k;   if (e.hash == hash && ((k = e.key) == key || key.equals(k))) {    V oldValue = e.value;    e.value = value;    e.recordAccess(this);    return oldValue;   }  }  modCount++;  addEntry(hash, key, value, i);  return null; } public final int hash(Object k) {  int h = hashSeed;  if (0 != h && k instanceof String) {   return sun.misc.Hashing.stringHash42((String) k);  }  h ^= k.hashCode();  // 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); } public final int hashCode() {  return Objects.hashCode(getKey()) ^ Objects.hashCode(getValue())  } static int indexFor(int h, int length) {  // assert Integer.bitCount(length) == 1 : "length must be a non-zero power of 2";  return h & (length-1); }