Не выводит текст в JTextArea

public class TCPConnection {
 
    private final Socket socket;
    private final Thread thread;
    private final TCPConnectionListener eventListener;
    private final BufferedReader in;
    private final BufferedWriter out;
 
 
    public TCPConnection(TCPConnectionListener eventListener, String ipAddr, int port) throws IOException {
        this(eventListener, new Socket(ipAddr, port));
    }
 
    public TCPConnection(TCPConnectionListener eventListener, Socket socket) throws IOException {
        this.eventListener = eventListener;
        this.socket = socket;
        in = new BufferedReader(new InputStreamReader(socket.getInputStream(), Charset.forName("UTF-8")));
        out = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream(), Charset.forName("UTF-8")));
        thread = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    eventListener.onConnectionReady(TCPConnection.this);
                    while (!thread.isInterrupted()) {
                        eventListener.onReceiveString(TCPConnection.this, in.readLine());
                    }
                } catch (IOException e) {
                    eventListener.onException(TCPConnection.this, e);
                }
            }
        });
        thread.start();
    }
 
    public synchronized void sendString(String value) {
        try {
            out.write(value + "\r\n");
            out.flush();
        } catch (IOException e) {
            eventListener.onException(this, e);
            disconnect();
        }
    }
 
    public synchronized void disconnect() {
        thread.interrupt();
        try {
            socket.close();
        } catch (IOException e) {
            eventListener.onException(this, e);
        }
    }
 
    @Override
    public String toString() {
        return "TCPConnection: " + socket.getInetAddress() + ": " + socket.getPort();
    }
 
}

public class Client extends JFrame implements ActionListener, TCPConnectionListener {
 
    private static final String IP_ADDRESS = "localhost";
    private static final int PORT = 8189;
    private static int WIDTH = 600;
    private static int HEIGHT = 400;
 
    private TCPConnection connection;
    private int port;
    private String host;
 
    public static void main(String[] args) {
        String address = args.length <= 0 ? IP_ADDRESS : args[0];
        int port = args.length <= 0 ? PORT : Integer.parseInt(args[1]);
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Client(address, port);
            }
        });
    }
 
    private final JTextArea log = new JTextArea();
    private final JTextField fieldInput = new JTextField();
 
    public Client(String host, int port) {
 
        this.port = port;
        this.host = host;
 
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setSize(WIDTH, HEIGHT);
        setLocationRelativeTo(null);
        setVisible(true);
        log.setEditable(false);
        log.setLineWrap(true);
        fieldInput.addActionListener(this);
 
        add(log, BorderLayout.CENTER);
        add(fieldInput, BorderLayout.SOUTH);
        add(new JScrollPane(log), BorderLayout.CENTER);
 
        setVisible(true);
 
        try {
            connection = new TCPConnection(this, host, port);
        } catch (IOException e) {
            printMessage("Connection exception: " + e);
        }
    }
 
    @Override
    public void actionPerformed(ActionEvent e) {
        String msg = fieldInput.getText();
        if (msg.equals("")) return;
        fieldInput.setText("");
        connection.sendString(msg + " = " + Calculator.calculate(msg));
    }
 
 
    @Override
    public void onConnectionReady(TCPConnection tcpConnection) {
        printMessage("Connection ready! Address: " + host + ", Port: " + port);
        printMessage("Please enter a expression in style like this: 18*(20-12)+40/2*(2+6)");
    }
 
    @Override
    public void onReceiveString(TCPConnection tcpConnection, String value) {
        printMessage(value);
    }
 
    @Override
    public void onException(TCPConnection connection, Exception ex) {
        printMessage("Connection exception: " + ex);
    }
 
    private synchronized void printMessage(String msg) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                log.append(msg + "\r\n");
                log.setCaretPosition(log.getDocument().getLength());
            }
        });
    }
}

public class Server implements TCPConnectionListener {
 
    private final static int PORT = 8189;
    private final static String IP_ADDRESS = "localhost";
 
 
    public static void main(String[] args) {
        String address = args.length <= 0 ? IP_ADDRESS : args[0];
        int port = args.length <= 0 ? PORT : Integer.parseInt(args[1]);
        new Server(address,port);
    }
 
    private TCPConnection tcpConnection;
 
    public Server(String address, int port) {
        System.out.println("Server runner");
 
        try (ServerSocket serverSocket = new ServerSocket(port)) {
            while (true) {
                try {
                    tcpConnection = new TCPConnection(this, serverSocket.accept());
                } catch (IOException e){
                    System.out.println("TCPConnection exception: " + e);
                }
            }
        } catch (IOException ex) {
            throw new RuntimeException();
        }
 
    }
 
    @Override
    public synchronized void onConnectionReady(TCPConnection tcpConnection) {
        tcpConnection.sendString("Client connected: "+ tcpConnection);
    }
 
    @Override
    public synchronized void onReceiveString(TCPConnection tcpConnection, String value) {
        tcpConnection.sendString(value);
    }
 
    @Override
    public synchronized void onException(TCPConnection connection, Exception ex) {
        System.out.println("TCPConnection exception: " + ex);
    }
 
}