public void closeServer() throws IOException {
  if (!serverIsOpen()) {
    return;
  }
  serverSocket.close();
  serverSocket=null;
  serverInput=null;
  serverOutput=null;
}

public void closeServer ( ) throws IOException { if ( ! serverIsOpen ( ) ) { return ; } serverSocket . close ( ) ; serverSocket = null ; serverInput = null ; serverOutput = null ; }
close an open connection to the server .
