Java tutorial
import java.awt.event.ContainerAdapter; import java.awt.event.ContainerEvent; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JProgressBar; import javax.swing.SwingUtilities; public class Main extends JPanel { JProgressBar jProgressBar1 = new JProgressBar(0, 100); public Main() { addContainerListener(new ContainerAdapter() { @Override public void componentAdded(ContainerEvent e) { if (jProgressBar1 == e.getChild()) { new Thread(new Task()).start(); } } }); jProgressBar1.setName(""); jProgressBar1.setValue(0); jProgressBar1.setStringPainted(true); add(jProgressBar1); } private class Task implements Runnable { long SLEEP_TIME = 100; @Override public void run() { for (int i = 0; i <= 100; i++) { final int progress = i; SwingUtilities.invokeLater(new Runnable() { public void run() { jProgressBar1.setValue(progress); } }); try { Thread.sleep(SLEEP_TIME); } catch (Exception e) { e.printStackTrace(); } } } } public static void main(String[] args) { Main mainPanel = new Main(); JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.getContentPane().add(mainPanel); frame.pack(); frame.setLocationByPlatform(true); frame.setVisible(true); } }