code: public void checkpointEnd()
    {
      if (! _isWhileCheckpoint) {
        throw new IllegalStateException();
      }
      
      _isWhileCheckpoint = false;
      
      byte []headerBuffer = _headerBuffer;
      BitsUtil.writeInt16(headerBuffer, 0, CHECKPOINT_END);
      writeImpl(headerBuffer, 0, 2);
      
      flush();
      
      _lastCheckpointEnd = _index - _startAddress;
      
      writeTail(_os);
    }
docs: Closes the previous epoch. Journal entries in a closed epoch will not
  be replayed on a journal restore.