code: @Override
    public V get(Object key)
    {
      if (key == null)
        return _nullValue;
  
      int hash = key.hashCode() & _mask;
      int count = _size + 1;
  
      K []keys = _keys;
  
      for (; count > 0; count--) {
        K mapKey = keys[hash];
  
        if (mapKey == null)
          return null;
  
        if (key.equals(_keys[hash]))
          return _values[hash];
  
        hash = (hash + 1) & _mask;
      }
  
      return null;
    }
docs: Get an item from the cache and make it most recently used.
  
  @param key key to lookup the item
  @return the matching object in the cache