);      BufferedInputStream input = new BufferedInputStream(System.in);     BufferedOutputStream output = new BufferedOutputStream(System.out);      byte[] receiveData = new byte[BUF_SIZE];     byte[] sendData = new byte[BUF_SIZE];     byte[] buf = new byte[BUF_SIZE];     String sentence;      if(System.in.available() > 0) {         DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);         serverSocket.receive(receivePacket);         