Как мне заставить 2 компьютера общаться друг с другом в java для обмена мгновенными сообщениями?

Я уже некоторое время работаю над мессенджером только в java-коде. Я могу заставить его работать, только если я запускаю сервер и клиент на одном компьютере, тогда они общаются. Но я не могу подключить 2 разных компьютера к одному серверу и обмениваться данными. Я посмотрел на много примеров, и я до сих пор не понимаю, что нужно изменить. Я покажу код ниже, большую его часть можно игнорировать, нужно смотреть только на сетевую часть. Серверное соединение находится в нижней части клиентского кода. Я новичок, и я ценю любую помощь. Спасибо.

Код клиента:

import javax.swing.*;
import javax.swing.text.DefaultCaret;

import java.awt.*;
import java.awt.event.*;
import java.text.*;
import java.util.Date;
import java.net.*;
import java.io.*;



public class NukeChatv3 extends JFrame
{

private JTextArea showtext;
private JTextField usertext;
private String hostname;
private Socket connectionsock;
private BufferedReader serverinput;
private PrintWriter serveroutput;
private int port;


private static final long serialVersionUID = 1L;

private class entersend implements KeyListener
{
      public void keyTyped ( KeyEvent e )
      {  

      }  
      public void keyPressed ( KeyEvent e)
      {  
          String text = usertext.getText();

          if(e.getKeyCode()== KeyEvent.VK_ENTER)
          {
              if (usertext.getText().equals(""))
                    return;
                else
                {
                    //try{
                    serveroutput.println(text);

                    usertext.setText("");
                    //showtext.append("[" + ft.format(dNow) + "]" + "\n" + "UserName: " + serverdata +"\n\n");
                    //}
                    /*catch(IOException in)
                    {
                        showtext.append(in.getMessage());
                    }*/

                }
          }
          else 
              return;
      }  
      public void keyReleased ( KeyEvent e )
      {  

      } 
}

private class sender implements ActionListener
{
    public void actionPerformed(ActionEvent e)
    {
        if (usertext.getText().equals(""))
            return;
        else
        {
            Date dNow = new Date( );
            SimpleDateFormat ft = new SimpleDateFormat ("hh:mm:ss");
            String text = usertext.getText();
            usertext.setText("");

            //* Send message to server



            showtext.append(ft.format(dNow) + "\n" + "UserName: " + text +"\n\n");
        }
    }
}

private class startconnection implements ActionListener
{
    public void actionPerformed(ActionEvent e)
    {
        clientconnection connect = new clientconnection();
        connect.start();
    }
}

private class CheckOnExit implements WindowListener
{
    public void windowOpened(WindowEvent e)
    {}

    public void windowClosing(WindowEvent e)
    {
        ConfirmWindow checkers = new ConfirmWindow( );
        checkers.setVisible(true);
    }

    public void windowClosed(WindowEvent e)
    {}

    public void windowIconified(WindowEvent e)
    {}

     public void windowDeiconified(WindowEvent e)
    {}

    public void windowActivated(WindowEvent e)
    {}

    public void windowDeactivated(WindowEvent e)
    {}
}


private class ConfirmWindow extends JFrame implements ActionListener
{

    private static final long serialVersionUID = 1L;

    public ConfirmWindow( )
    {
        setSize(200, 100);
        getContentPane( ).setBackground(Color.LIGHT_GRAY);
        setLayout(new BorderLayout( ));

        JLabel confirmLabel = new JLabel(
                       "Are you sure you want to exit?");
        add(confirmLabel, BorderLayout.CENTER);

        JPanel buttonPanel = new JPanel( );
        buttonPanel.setBackground(Color.GRAY);
        buttonPanel.setLayout(new FlowLayout( ));

        JButton exitButton = new JButton("Yes");
        exitButton.addActionListener(this);
        buttonPanel.add(exitButton);

        JButton cancelButton = new JButton("No");
        cancelButton.addActionListener(this);
        buttonPanel.add(cancelButton);

        add(buttonPanel, BorderLayout.SOUTH);
    }

    public void actionPerformed(ActionEvent e) 
    {
        String actionCommand = e.getActionCommand( );

        if (actionCommand.equals("Yes")) 
            System.exit(0);
        else if (actionCommand.equals("No"))
            dispose( );
        else
            System.out.println("Unexpected Error in Confirm Window.");
    }
}


public static void main(String[] args) 
{

    NukeChatv3 nuke = new NukeChatv3();
    nuke.setVisible(true);

}

public NukeChatv3()
{       
        setTitle("NukeChat v3");
        setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        setSize(550, 400);
        setResizable(false);
        addWindowListener(new CheckOnExit());
        addWindowListener(new WindowAdapter(){
            public void windowOpened(WindowEvent e){
                usertext.requestFocus();
            }
        });
        getContentPane().setBackground(Color.BLACK);
        setLayout(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();

        showtext = new JTextArea(15, 35);
        showtext.setEditable(false);
        showtext.setLineWrap(true);
        DefaultCaret caret = (DefaultCaret)showtext.getCaret();
        caret.setUpdatePolicy(DefaultCaret.ALWAYS_UPDATE);


        JScrollPane scrollbar = new JScrollPane(showtext);
        scrollbar.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
        scrollbar.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
        c.anchor = GridBagConstraints.FIRST_LINE_START;
        //c.gridwidth = 2;
        c.insets = new Insets(20, 20, 20, 20);
        c.weightx = .5;
        c.weighty = .5;
        c.gridx = 0;
        c.gridy = 0;
        add(scrollbar, c);

        usertext = new JTextField(35);

        usertext.requestFocusInWindow();
        usertext.addKeyListener(new entersend());
        //c.gridwidth = 1;
        c.insets = new Insets(0, 20, 0, 0);
        c.weightx = .5;
        c.gridx = 0;
        c.gridy = 1;
        add(usertext, c);

        JPanel empty = new JPanel();
        c.gridx = 1;
        c.gridy = 0;
        empty.setLayout(new GridLayout(2,1));

        JButton test1 = new JButton("test1");
        empty.add(test1);

        JButton test2 = new JButton("test2");
        empty.add(test2);

        add(empty, c);

        JButton send = new JButton("Send");
        send.addActionListener(new sender());
        c.ipady = -5;
        c.insets = new Insets(0, 0, 20, 0);
        c.gridx = 1;
        c.gridy = 1;
        add(send, c);

        JMenu menu = new JMenu("File");
        JMenuItem connection = new JMenuItem("Connect");
        connection.addActionListener(new startconnection());
        menu.add(connection);

        JMenuBar bar = new JMenuBar();
        bar.add(menu);
        setJMenuBar(bar);



}

private class clientconnection  extends Thread
{
    public void run()
    {
        try
        {
            // Set host name and port//
            hostname = "localhost";
            port = 16666;

            // connect to socket of the server//
            connectionsock = new Socket(hostname, port);

            // set up client input from server//
            serverinput = new BufferedReader(new InputStreamReader(connectionsock.getInputStream()));

            // set up client output to server//
            serveroutput = new PrintWriter(connectionsock.getOutputStream(), true);

            // set up a looping thread to constantly check if server has sent anything 
            String serverdata = "";

            while ((serverdata = serverinput.readLine()) != null)
            {
                Thread.sleep(500);
                Date dNow = new Date( );
                SimpleDateFormat ft = new SimpleDateFormat ("hh:mm:ss");
                showtext.append("[" + ft.format(dNow) + "]" + "\n" +"Recieved from server: \n" + "UserName: " + serverdata +"\n\n");
            }

        }

        catch(IOException e)
        {
            System.out.println(e.getMessage());
        }
        catch(InterruptedException inter)
        {
            showtext.append("Unexpected interruption\n\n");
        }
    }


}

}

Код сервера:

import java.net.ServerSocket;
import java.io.*;
import java.net.Socket;
import java.io.DataOutputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;



public class servertest extends JFrame
{

private JButton start;
private JTextArea text;
private BufferedReader clientinput;
private PrintWriter clientoutput;

private class listen implements ActionListener
{
    public void actionPerformed(ActionEvent e)
    {
        connection connect = new connection();
        connect.start();
    }
}

public servertest ()
{
    setSize(400,300);
    setLayout(new BorderLayout());
    start = new JButton("Start");
    start.addActionListener(new listen());
    add(start, BorderLayout.SOUTH);

    text = new JTextArea(6, 10);
    text.setEditable(false);
    add(text, BorderLayout.CENTER);
}
private class connection extends Thread
{
    public void run()
    {
    try
    {
        // Sets up a server socket with set port//
        text.setText("Waiting for connection on port 16666");
        ServerSocket serversock = new ServerSocket(16666);

        // Waits for the Client to connect to the server//
        Socket connectionsock = serversock.accept();

        // Sets up Input from the Client to go to the server//
        clientinput = new BufferedReader(new InputStreamReader(connectionsock.getInputStream()));

        // Sets up data output to send data from server to client//
        clientoutput = new PrintWriter(connectionsock.getOutputStream(), true);

        // Test server to see if it can perform a simple task//
        text.setText("Connection made, waiting to client to send there name");
        clientoutput.println("Enter your name please.");

        // Get users name//
        String clienttext = clientinput.readLine();

        // Reply back to the client//
        String replytext = "Welcome " + clienttext;
        clientoutput.println(replytext);
        text.setText("Sent: " + replytext);

        while ((replytext = clientinput.readLine()) != null)
        {
            clientoutput.println(replytext);
            text.setText("Sent: " + replytext);
        }

        // If you need to close the Socket connections
        // clientoutput.close();
        // clientinput.close();
        // connetionsock.close();
        // serversock.close();

    }

    catch(IOException e)
    {
        System.out.println(e.getMessage());
    }
    }
}

public static void main(String[] args)
{
    servertest test = new servertest();
    test.setVisible(true);
}