code: public void unlock() throws IOException {
      if (fileLock != null) {
        try {
          fileLock.release();
        } catch (ClosedChannelException e) {
        }
        fileLock = null;
      }
    }
docs: /*
  (non-Javadoc)
  
  @see com.orientechnologies.orient.core.storage.fs.OFileAAA#unlock()