Problem in repainting jtextarea

Question

My requirement is, client has to sent string messages and server has to receive these messages and display it in jtextarea. In my code sending and receiving are done properly, but the problem is the jtextarea is not updated, it goes blank.
I have attached the client and server files, can anyone solve my problem?
Thanks in advance.
//server file
import java.net.*;
import java.io.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.event.*;
import java.util.*;
import java.text.*;
import java.awt.*;
import java.awt.event.*;
public class MessageCenter extends javax.swing.JFrame {
    public MessageCenter() {
        initComponents();
    private void initComponents() {
        jLabel1 = new JLabel();
        jScrollPane1 = new JScrollPane();
        jTextArea1 = new JTextArea();
        jPanel1 = new JPanel();
        jLabel5 = new JLabel();
        jLabel3 = new JLabel();
        jButton1 = new JButton();
        jButton2 = new JButton();
        jLabel2 = new JLabel();
        jLabel4 = new JLabel();
        menuBar = new JMenuBar();
        fileMenu = new JMenu();
        Start = new JMenuItem();
        jSeparator1 = new JSeparator();
        Stop = new JMenuItem();
        jSeparator2 = new JSeparator();
        Exit = new JMenuItem();
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setTitle("Message Center");
        setMaximizedBounds(new java.awt.Rectangle(0, 0, 560, 700));
        setBounds(0,0,600,700);
        setName("");
        jLabel1.setBackground(new java.awt.Color(255, 255, 255));
        jLabel1.setFont(new java.awt.Font("Georgia", 1, 24));
        jLabel1.setForeground(new java.awt.Color(34, 44, 106));
        jLabel1.setHorizontalAlignment(SwingConstants.CENTER);
        jLabel1.setText("Message Center");
        jLabel1.setIconTextGap(0);
        getContentPane().add(jLabel1, java.awt.BorderLayout.NORTH);
        jTextArea1.setColumns(20);
        jTextArea1.setFont(new java.awt.Font("Book Antiqua", 0, 12));
        jTextArea1.setLineWrap(true);
        jTextArea1.setRows(25);
        jTextArea1.setBorder(null);
        jScrollPane1.setViewportView(jTextArea1);
        getContentPane().add(jScrollPane1, java.awt.BorderLayout.CENTER);
        jPanel1.setLayout(new java.awt.GridLayout(1, 6, 10, 5));
        jPanel1.add(jLabel5);
        jPanel1.add(jLabel3);
        jButton1.setText("Start");
        jPanel1.add(jButton1);
        jButton2.setText("Stop");
        jPanel1.add(jButton2);
        jPanel1.add(jLabel2);
        jPanel1.add(jLabel4);
        getContentPane().add(jPanel1, java.awt.BorderLayout.SOUTH);
        fileMenu.setText("File");
        Start.setText("Start");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                System.out.println("hello");
                StartActionPerformed(evt);
        fileMenu.add(Start);
        fileMenu.add(jSeparator1);
        Stop.setText("Stop");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                StopActionPerformed(evt);
        fileMenu.add(Stop);
        fileMenu.add(jSeparator2);
        Exit.setText("Exit");
        fileMenu.add(Exit);
        menuBar.add(fileMenu);
        setJMenuBar(menuBar);
        pack();
private void StartActionPerformed(java.awt.event.ActionEvent evt)  {
          try{
                    Server t=new Server(jTextArea1);
                    t.listenSocket();
          catch(Exception e)
          e.printStackTrace();
    private void StopActionPerformed(java.awt.event.ActionEvent evt) {
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new MessageCenter().setVisible(true);
    private JMenuItem Exit;
    private JMenuItem Start;
    private JMenuItem Stop;
    private JMenu fileMenu;
    private JButton jButton1;
    private JButton jButton2;
    private JLabel jLabel1;
    private JLabel jLabel2;
    private JLabel jLabel3;
    private JLabel jLabel4;
    private JLabel jLabel5;
    private JPanel jPanel1;
    private JScrollPane jScrollPane1;
    private JSeparator jSeparator1;
    private JSeparator jSeparator2;
    public JTextArea jTextArea1;
    private JMenuBar menuBar;
class ClientThread implements Runnable {
  private Socket client;
  JTextArea jt;
  ClientThread(Socket client,JTextArea jt) {
   this.client = client;
   this.jt=jt;
  public void run(){
    try{
           //DataInputStream dis= new DataInputStream(client.getInputStream());
            DataInputStream dis= new DataInputStream(new BufferedInputStream(client.getInputStream()));
           System.out.println("client connected");
           //BufferedReader dis = new BufferedReader(new InputStreamReader(s.getInputStream()));
               String msg=null;
               byte msg1[]=new byte[200];
            while(true)
               try{
               if(dis.available()>0)
               dis.readFully(msg1,0,dis.available());
             //  System.out.println("Msg is ==> "+new String(msg1));
               new PrinterThread(jt,new String(msg1)).start();
               msg1=new byte[200];
               Thread.sleep(1000);
                  }catch (Exception e) {
                     System.out.println("Exception  ");
         } catch (IOException e) {
                     System.out.println("Exception occurred");
class Server {
          JTextArea jt;
          public Server(JTextArea jt)
               this.jt=jt;
          public void listenSocket() throws Exception
          ServerSocket ss=null;
          try{
          ss=new ServerSocket(8000);
          System.out.println("Server started");
         catch (IOException e) {
                     System.out.println("Exception");
                     System.exit(-1);
         while(true){
           ClientThread w;
           try{
        w = new ClientThread(ss.accept(),jt);
        Thread t = new Thread(w);
        t.start();
            catch (IOException e) {
        System.out.println("Accept failed: 8000");
       public static void main(String args[])throws Exception {
          /*Server t=new Server();
          t.listenSocket();*/
     class PrinterThread extends Thread
            public PrinterThread(JTextArea jt1,String msg)
             jTextArea1 = jt1;
             this.msg=msg;
             System.out.println("PrinterThread constructor ");
            public void run()
             try
                Date today;
                SimpleDateFormat formatter;
                String output;
                 String pattern="dd.MM.yyyy '@' H:mm";
                formatter = new SimpleDateFormat(pattern);
                today = new Date();
                output = formatter.format(today);
                    System.out.println(" "+output+"  "+msg+" \n");
                      jTextArea1.append(" "+output+"  "+msg+" \n");
                      jTextArea1.updateUI();
                         jTextArea1.revalidate();
//                      JOptionPane.showMessageDialog(null,"hi");
                      //System.out.println("Get text "+jTextArea1.getText());
             catch (Exception exception) {}
            private JComboBox combo;
            private JTextArea jTextArea1;
            String msg=null;
//client.java
import java.net.*;
import java.io.*;
import java.io.File;
public class client {
       public static void main(String args[]) {
               try {
                       Socket ss=new Socket(InetAddress.getLocalHost(),8000);
                       DataOutputStream dos=new DataOutputStream(ss.getOutputStream());
                       for(int i=1;i<100;i++){
                          if((i%2)==0)
                        dos.writeBytes("1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,3233");
                          else
                        dos.writeBytes("1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42");
                       Thread.sleep(5000);
               catch(Exception e) {
               e.printStackTrace();
               System.out.println(" ");
}

Answer 1

You need to run your Server in a separate Thread.
Right now its running in the GUI Event Thread.I created new thread for my server, now it's updating jtextarea.
Thank you very much.