import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public final class Main extends JDialog
                        implements WindowListener, ActionListener {

    private final JLabel lbl
                = new JLabel("Press the button to open a simple file chooser:");
    private final JButton btn
                = new JButton("Open!");

    public static void main(String args[]) {
        new Main().runDialog();
    }

    public Main() {
        getContentPane().add(lbl, BorderLayout.NORTH);
        getContentPane().add(btn, BorderLayout.CENTER);
        btn.addActionListener(this);
        addWindowListener(this);
        
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    private void runDialog() {
        Font currFont = btn.getFont();
        pack();
        btn.setFont(currFont.deriveFont((float)(currFont.getSize() * 3.0d)));
        pack();
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        JFileChooser fileChooser = new JFileChooser();
        fileChooser.showOpenDialog(null);
    }

    public void windowClosing(WindowEvent e) {
        dispose();
        System.exit(1);
    }

    public void windowOpened(WindowEvent windowevent) {
    }

    public void windowIconified(WindowEvent windowevent) {
    }

    public void windowDeiconified(WindowEvent windowevent) {
    }

    public void windowDeactivated(WindowEvent windowevent) {
    }

    public void windowClosed(WindowEvent windowevent) {
    }

    public void windowActivated(WindowEvent windowevent) {
    }

}