JCombo di atas JButton

Assalamu'alaikum wr.wb

pas bangun tidur, e kepikiran lgi project combo yg blm jd akhirnya jdnya jcombo di atas jbutton,,,,, lngsung k codingnya aja ya,,,
package combo;

import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

/**
 *
 * @author tiwi
 */
public class Coba extends JFrame {

    JComboBox cb;
    JButton b;
    JLabel l1, l2;
    JPanel p1, p2;

    public Coba() {
        initComponent();
        initLayout();
        initAction();
    }

    private void initComponent() {
        b = new JButton();
        String[] gambar = {"-pilih-", "icon", "home", "chat"};
        cb = new JComboBox(gambar);
        l1 = new JLabel("ComBo");
        l2 = new JLabel();
        p1 = new JPanel();
        p2 = new JPanel();
    }

    private void initLayout() {
        b.setLayout(new FlowLayout());
        b.add(cb);
        b.setBackground(Color.BLUE);
        Container c = getContentPane();
        c.setLayout(new BoxLayout(c, BoxLayout.Y_AXIS));
        c.add(p1);
        c.add(p2);
        p1.setLayout(new FlowLayout());
        p1.add(b);
        p2.setLayout(new FlowLayout());
        p2.add(l1);
        p2.add(l2);
        c.setSize(400, 300);
        setVisible(true);
        pack();
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
    }

    private void initAction() {
        b.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                if (cb.getSelectedIndex() == 1) {
                    l2.setIcon(new ImageIcon("src/Icon.png"));
                } else if (cb.getSelectedIndex() == 2) {
                    l2.setIcon(new ImageIcon("src/Home.png"));
                }
                else if (cb.getSelectedIndex() == 3) {
                    l2.setIcon(new ImageIcon("src/Chat.png"));
                }
            }
        });
    }
}
screenshotnya:

nah jdnya action combonya di dapat ktika buttonya d klik......
oke selamat mencoba ya..... jngn lupa kritik dan saranya.....


Wassalamu'allaikum Wr.WB.....