private static DatagramSocket sock;
    private int portNumber;

    public UdpSrv(int portNumber) {
        this.portNumber = portNumber;
    }

    public void run() {
        byte[] data = new byte[300];
        int i, len;
        String message;

//        if (args.length < 1) {
//            System.out.println("Need to have port number as argument");
//            System.exit(1);
//        }
        try {
//            portNumber = Integer.parseInt(args[0]);
            sock = new DatagramSocket(portNumber);
        } catch (BindException ex) {
            System.out.println("Bind to local port failed");
            System.exit(1);
        } catch (SocketException ex) {
            Logger.getLogger(UdpSrv.class.getName()).log(Level.SEVERE, null, ex);
        }

        DatagramPacket udpPacket = new DatagramPacket(data, data.length);

        System.out.println("Listening for UDP requests (IPv6/IPv4). Use CTRL+C to terminate the server");
        while (true) {
            udpPacket.setData(data);
            udpPacket.setLength(data.length);
            try {
                sock.receive(udpPacket);

                len = udpPacket.getLength();
                message = new String(udpPacket.getData(), 0, udpPacket.getLength());
                System.out.println("Request from: " + udpPacket.getAddress().getHostAddress()
                        + " port: " + udpPacket.getPort() + " message: " + message);

                udpPacket.setData(message.getBytes());
                udpPacket.setLength(message.length());
                sock.send(udpPacket);
            } catch (IOException ex) {
                Logger.getLogger(UdpSrv.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

    public boolean addMessage(String mensagem) {
        mensagem = mensagem.trim();
        if(mensagem.charAt(0) == '@'){
            String mensagemArr[] = mensagem.split(" ");
            String mensagemAux = "";
            String wall = mensagemArr[0];
            for(int i = 1; i < mensagemArr.length; i++) {
                mensagemAux += mensagemArr[i] + " ";
            }
            HttpServerWall.addMessageToWall(wall, mensagemAux);
            return true;
        }else {
            return false;
        }
    }