code: @Override
    protected final long readAndUpdateIDCounter (@Nonnegative final int nReserveCount)
    {
      final String sContent = SimpleFileIO.getFileAsString (m_aFile, CHARSET_TO_USE);
      final long nRead = sContent != null ? StringParser.parseLong (sContent.trim (), 0) : 0;
      SimpleFileIO.writeFile (m_aFile, Long.toString (nRead + nReserveCount), CHARSET_TO_USE);
      return nRead;
    }
docs: /*
  Note: this method must only be called from within a locked section!