put.java

public V put(K key, V value) {
  ...  
  index = ~index; //NOT -1 = 0 
  ...
  mHashes[index] = hash;
  mArray[index<<1] = key; //XOR 1 == 0
  mArray[(index<<1)+1] = value; //XOR 1 + 1 == 1
  return null //previous value
}