UserThird.java

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import javax.swing.*;
import javax.swing.border.*;

public class UserThird implements ActionListener, Runnable {
    
    JTextField text;
    JPanel a1;
    static Box vertical = Box.createVerticalBox();
    static JFrame f = new JFrame();
    
    BufferedReader reader;
    BufferedWriter writer;
    String name = "Babblu Bhaiya";
    
    UserThird() {
        
        f.setLayout(null);
        
        JPanel p1 = new JPanel();
        p1.setBackground(new Color(7, 94, 84));
        p1.setBounds(0, 0, 450, 70);
        p1.setLayout(null);
        f.add(p1);
        
        JLabel nameLabel = new JLabel("Mirzapur");
        nameLabel.setBounds(110, 15, 200, 18);
        nameLabel.setForeground(Color.WHITE);
        nameLabel.setFont(new Font("SAN_SERIF", Font.BOLD, 18));
        p1.add(nameLabel);
        
        a1 = new JPanel();
        a1.setBounds(5, 75, 440, 570);
        a1.setBackground(Color.WHITE);
        a1.setLayout(new BorderLayout());   // IMPORTANT
        f.add(a1);
        
        text = new JTextField();
        text.setBounds(5, 655, 310, 40);
        text.setFont(new Font("SAN_SERIF", Font.PLAIN, 16));
        f.add(text);
        
        JButton send = new JButton("Send");
        send.setBounds(320, 655, 123, 40);
        send.setBackground(new Color(7, 94, 84));
        send.setForeground(Color.WHITE);
        send.addActionListener(this);
        f.add(send);
        
        f.setSize(450, 700);
        f.setLocation(950, 50);
        f.setUndecorated(true);
        f.setVisible(true);
        
        try {
            Socket socket = new Socket("localhost", 6001);
            writer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
            reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            System.out.println("UserThird connected");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    public void actionPerformed(ActionEvent ae) {
        try {
            String out = name + ": " + text.getText();   // SIMPLIFIED
            
            JPanel p2 = formatLabel(out);
            
            JPanel right = new JPanel(new BorderLayout());
            right.setBackground(Color.WHITE);
            right.add(p2, BorderLayout.LINE_END);
            vertical.add(right);
            vertical.add(Box.createVerticalStrut(15));
            
            a1.add(vertical, BorderLayout.PAGE_START);
            
            writer.write(out);
            writer.write("\r\n");
            writer.flush();
            
            text.setText("");
            
            f.repaint();
            f.validate();   
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    public static JPanel formatLabel(String out) {
        JPanel panel = new JPanel();
        panel.setBackground(Color.WHITE);
        panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
        
        JLabel output = new JLabel(out);
        output.setFont(new Font("Tahoma", Font.PLAIN, 16));
        output.setBackground(new Color(37, 211, 102));
        output.setOpaque(true);
        output.setBorder(new EmptyBorder(5, 10, 5, 10));
        
        panel.add(output);
        return panel;
    }
    
    public void run() {
        try {
            String msg;
            while(true) {
                msg = reader.readLine();
                if (msg.startsWith(name)) continue;
                
                JPanel panel = formatLabel(msg);
                
                JPanel left = new JPanel(new BorderLayout());
                left.setBackground(Color.WHITE);
                left.add(panel, BorderLayout.LINE_START);
                vertical.add(left);
                
                a1.add(vertical, BorderLayout.PAGE_START);
                
                f.repaint();
                f.validate();   
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args) {
        UserThird third = new UserThird();
        Thread t1 = new Thread(third);
        t1.start();
    }
}