Loading

import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.List;
import java.util.concurrent.ExecutionException;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;

public class MainFrame extends JFrame {

    private JLabel countLabel1 = new JLabel("0");
    private JLabel statusLabel = new JLabel("Task not completed.");
    private JButton startButton = new JButton("Start");

    public MainFrame(String title) {
        super(title);
        setLayout(new GridBagLayout());
        countLabel1.setFont(new Font("serif", Font.BOLD, 28));
        GridBagConstraints gc = new GridBagConstraints();
        gc.fill = GridBagConstraints.NONE;
        gc.gridx = 0;
        gc.gridy = 0;
        gc.weightx = 1;
        gc.weighty = 1;
        add(countLabel1, gc);
        gc.gridx = 0;
        gc.gridy = 1;
        gc.weightx = 1;
        gc.weighty = 1;
        add(statusLabel, gc);
        gc.gridx = 0;
        gc.gridy = 2;
        gc.weightx = 1;
        gc.weighty = 1;
        add(startButton, gc);
        startButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                start();
            }
        });
        setSize(200, 400);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }

    private void start() {
        Thread worker = new Thread() {
            public void run() {

                // Simulate doing something useful.
                for (int i = 0; i <= 10; i++) {
                    // Bad practice
                    countLabel1.setText(Integer.toString(i));

                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                    }
                }

                // Bad practice
                statusLabel.setText("Completed.");
            }
        };

        worker.start();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new MainFrame("SwingWorker Demo");
            }
        });
    }
}