TextArea append information during process?

Question

I have a system that append information in one textarea, I would like that textarea shows the information being appended in the moment.
To start the append, I click in a button. Then I click in the button, the information shows in the textarea when the process finished only and not during process.
Below is one similar code with the problem.
Thanks by help.
import javax.swing.*;
import java.awt.event.*;
public class test extends JFrame implements ActionListener {
    public test() {
        cmdStartCapture.addActionListener(this);
        pnlGeral.setLayout(null);
        cmdStartCapture.setBounds(30,40, 200, 26);
        pnlGeral.add(cmdStartCapture); 
        scpDataCaptured.setBounds(50,200, 200, 300);
        scpDataCaptured.setViewportView(txaDataCaptured);
        pnlGeral.add(scpDataCaptured);
        pnlGeral.setBounds(0,0, 800, 700);
        pnlGeral.setLayout(null);
        getContentPane().add(pnlGeral);
        setBounds(10,10, 800, 700);
        setVisible(true);   
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitSystem();
       // IF I ENABLE THIS LINE TO THE PROCESS RUN WITH SYSTEM
      // INITIALIZATION, THE INFORMATION IS SHOW DURING PROCESS
       //cmdStartCapture.doClick();
    private void exitSystem() {
       setVisible(false);
        dispose();
        System.exit(0);
    public static void main(String[] args) {
        test system = new test();
    public void actionPerformed(ActionEvent event) {
        Object selobj = event.getSource();      
        if (selobj == cmdStartCapture) {
           // IF THE PROCESS RUN THROUGH BUTTON CLICK
          // THE TEXTAREA SHOW INFORMATION WHEN PROCESS
         //  FINISHED.
            cmdStartCapture() ;
    private void cmdStartCapture() {         
            int i = 0, cont=200000;           
            while (i<cont) {         
                txaDataCaptured.append("\n test " + i );                 
                i = i + 1;               
    private JPanel pnlGeral = new JPanel();
    private JButton cmdStartCapture = new JButton("Start");
    public static JTextArea txaDataCaptured = new JTextArea();
    private JScrollPane scpDataCaptured = new JScrollPane();
}

Answer 1

where is thread part ?
import javax.swing.*;
import java.util.*;
import java.awt.event.*;
public class testThis extends JFrame implements ActionListener,Runnable {
    public testThis() {
        cmdStartCapture.addActionListener(this);
        pnlGeral.setLayout(null);
        cmdStartCapture.setBounds(30,40, 200, 26);
        pnlGeral.add(cmdStartCapture);
        scpDataCaptured.setBounds(50,200, 200, 300);
        scpDataCaptured.setViewportView(txaDataCaptured);
        pnlGeral.add(scpDataCaptured);
        pnlGeral.setBounds(0,0, 800, 700);
        pnlGeral.setLayout(null);
        getContentPane().add(pnlGeral);
        setBounds(10,10, 800, 700);
        setVisible(true);
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitSystem();
       // IF I ENABLE THIS LINE TO THE PROCESS RUN WITH SYSTEM
      // INITIALIZATION, THE INFORMATION IS SHOW DURING PROCESS
       //cmdStartCapture.doClick();
    private void exitSystem() {
       setVisible(false);
        dispose();
        System.exit(0);
    public static void main(String[] args) {
        testThis system = new testThis();
    public void actionPerformed(ActionEvent event) {
        Object selobj = event.getSource();
        if (selobj == cmdStartCapture) {
           // IF THE PROCESS RUN THROUGH BUTTON CLICK
          // THE TEXTAREA SHOW INFORMATION WHEN PROCESS
         //  FINISHED.
    //        cmdStartCapture() ;
          new Thread(this).start();
    private void cmdStartCapture() {
/*            int i = 0, cont=200000;
            while (i<cont) {
                txaDataCaptured.append("\n test " + i );
                i = i + 1;
    private JPanel pnlGeral = new JPanel();
    private JButton cmdStartCapture = new JButton("Start");
    public static JTextArea txaDataCaptured = new JTextArea();
    private JScrollPane scpDataCaptured = new JScrollPane();
        public void run()
            int i = 0, cont=200000;
            while (i<cont) {
                txaDataCaptured.append("\n test " + i );
                i = i + 1;
Hope This helps