@Override
    public void close() throws StorageException {
      try {
        if (USE_UNMAP_FOR_INDEX_DISPOSAL) {
          // unmap is required for correct index re-instantiation on windows,
          // but may result in JVM crash if we are not careful enough
          storage.closeAndUnsafelyUnmap();
        } else {
          storage.close();
        }
      }
      catch (IOException e) {
        throw new StorageException(e);
      }
    }
@Override
    public void close()