code: protected void closeDatagramChannel ()
      {
          if (_selector != null) {
              try {
                  _selector.close();
              } catch (IOException ioe) {
                  log.warning("Error closing selector: " + ioe);
              }
              _selector = null;
          }
          if (_datagramChannel != null) {
              log.debug("Closing datagram socket channel.");
  
              try {
                  _datagramChannel.close();
              } catch (IOException ioe) {
                  log.warning("Error closing datagram socket: " + ioe);
              }
              _datagramChannel = null;
  
              // clear these out because they are probably large and in charge
              _uout = null;
              _sequencer = null;
          }
      }
docs: Closes the datagram channel.