Dialog skeleton for page joiner project

/**
* Created with Simple GUI Extension for BlueJ
* http://home.pf.jcu.cz/~gbluej/
*/
import javax.swing.UIManager.LookAndFeelInfo;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import javax.swing.border.Border;
import javax.swing.*;
import java.util.Vector;
import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;

public class DialogSkeleton extends JDialog
{
    private JButton btnCancel;
    private JButton btnOK;
    private JCheckBox checkbox1;
    private JLabel lblTitle;
    private JList<String> listBox;
    private JPanel panel1;

    /** Create this dialog from a list of Strings */
    public DialogSkeleton(Vector<String> lines)
    {
        this.setModal(true);
        this.setTitle("DialogSkeleton");
        this.setSize(500,400);

        //pane with null layout
        JPanel contentPane = new JPanel(null);
        contentPane.setPreferredSize(new Dimension(500,400));
        contentPane.setBackground(new Color(192,192,192));

        btnCancel = new JButton();
        btnCancel.setBounds(391,350,90,35);
        btnCancel.setBackground(new Color(214,217,223));
        btnCancel.setForeground(new Color(0,0,0));
        btnCancel.setEnabled(true);
        btnCancel.setFont(new Font("DejaVu Sans",0,12));
        btnCancel.setText("Cancel");
        btnCancel.setVisible(true);

        btnOK = new JButton();
        btnOK.setBounds(288,350,90,35);
        btnOK.setBackground(new Color(214,217,223));
        btnOK.setForeground(new Color(0,0,0));
        btnOK.setEnabled(true);
        btnOK.setFont(new Font("DejaVu Sans",0,12));
        btnOK.setText("OK");
        btnOK.setVisible(true);

        checkbox1 = new JCheckBox();
        checkbox1.setBounds(16,350,130,35);
        checkbox1.setBackground(new Color(214,217,223));
        checkbox1.setForeground(new Color(0,0,0));
        checkbox1.setEnabled(true);
        checkbox1.setFont(new Font("DejaVu Sans",0,12));
        checkbox1.setText("Retain hyphens");
        checkbox1.setVisible(true);

        lblTitle = new JLabel();
        lblTitle.setBounds(7,5,279,16);
        lblTitle.setBackground(new Color(214,217,223));
        lblTitle.setForeground(new Color(0,0,0));
        lblTitle.setEnabled(true);
        lblTitle.setFont(new Font("DejaVu Sans",0,12));
        lblTitle.setText("Select lines that should NOT be joined.");
        lblTitle.setVisible(true);

        listBox = new JList<String>(lines);
        listBox.setBounds(5,29,477,311);
        listBox.setBackground(new Color(255,255,255));
        listBox.setForeground(new Color(0,0,0));
        listBox.setEnabled(true);
        listBox.setFont(new Font("Courier",0,12));
        listBox.setVisible(true);
        JScrollPane scrollPane = new JScrollPane(listBox);
        scrollPane.setBounds(5,29,477,311);

        panel1 = new JPanel(null);
        panel1.setBorder(BorderFactory.createEtchedBorder(1));
        panel1.setBounds(4,5,491,390);
        panel1.setBackground(new Color(214,217,223));
        panel1.setForeground(new Color(0,0,0));
        panel1.setEnabled(true);
        panel1.setFont(new Font("DejaVu Sans",0,12));
        panel1.setVisible(true);

        //adding components to contentPane panel
        panel1.add(btnCancel);
        panel1.add(btnOK);
        panel1.add(checkbox1);
        panel1.add(lblTitle);
        panel1.add(scrollPane, BorderLayout.CENTER);
        contentPane.add(panel1);

        //adding panel to JFrame and seting of window position and close operation
        this.add(contentPane);
        //this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setLocationRelativeTo(null);
        this.pack();
    }

     /** Accessor to checkbox state */
     public boolean retainHyphens()
     {
         return checkbox1.isSelected();
     }

     /** A local main for testing */
     public static void main(String[] args)
     {
        javax.swing.SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                String[] numbers = { "zero", "one", "two", "three", "four"};
                // Create the dialog
                DialogSkeleton jdlg = new DialogSkeleton(new Vector<String>(Arrays.asList(numbers)));
                // Make it visible and wait
                jdlg.setVisible(true);
                // After the dialog closes, do the following, just as a demo.
                System.out.print("Retain hyphens is: ");
                if (jdlg.retainHyphens())
                {
                    System.out.println("on.");
                }
                else
                {
                    System.out.println("off.");
                }
            }
        });
    }

}