public void createServer(int inPortNumber){

        if(inPortNumber <= 0){
            inPortNumber = DEFAULT_PORT_NUMBER;
        }

        portNumber = inPortNumber;

        try {
            serverSocket = new ServerSocket(portNumber);
        } catch (IOException e) {
            System.out.println("Порт занят: " + portNumber);
            System.exit(-1);
        }

    }