updateNextAvailableIndex(entry);
  private void addEntry(Entry entry)  {    int capacity = _entries.length;    int hash = entry._key.hashCode() & _hashMask;    for (int i = capacity; i >= 0; i--) {      if (_entries[hash] == null) {	_entries[hash] = entry;	entry._index = hash;	return;      }      hash = (hash + 1) & _hashMask;    }  }