return new byte[BUFFER_SIZE];
  }

  /**
   * There are three methods to implement {@link FileChannel#transferTo(long, long,
   * WritableByteChannel)}:
   *
   * <ol>
   *   <li>Use sendfile(2) or equivalent. Requires that both the input channel and the output
   *       channel have their own file descriptors. Generally this only happens when both channels

        final int sizeThreshold = getSizeThreshold();
        final File repository = createRepositoryFile();
        return DiskFileItemFactory.builder().setBufferSize(sizeThreshold).setFile(repository).get();
    }

    protected int getSizeThreshold() {
        return ComponentUtil.getFessConfig().getHttpFileuploadThresholdSizeAsInteger();
    }

    protected File createRepositoryFile() {