JPanel not repainting if embedded in another panel

Question

I have a reusable class called as DuplicatorPanel. This class has two add/ remove buttons like in Mac if you are familiar.
The problem is that the screen gets updated with an extra row in case i have a main method in Duplicator itself. However if i have that in another panel as in HyperlinkBuilder then it does not repaint itself.
Please can someone help ?
package sam.dnd;
import java.awt.event.ActionEvent;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
public abstract class DuplicatorPanel extends Box {
    private static final long serialVersionUID = 1L;
    private static int oneup = 0;
    private Map<String, JComponent> panelMap = new LinkedHashMap<String, JComponent>();
    private Action addAction;
    private Action removeAction;
    public DuplicatorPanel() {
        super(BoxLayout.Y_AXIS);
        this.initComponents();
        this.placeComponents();
    private void initComponents() {
        addAction = new AddAction();
        removeAction = new RemoveAction();
        addDuplicatorPanel();
    private void placeComponents() {
        Iterator<JComponent> itr = this.panelMap.values().iterator();
        while(itr.hasNext()) {
            JComponent comp = (JComponent) itr.next();
            this.add(comp);
        this.add(Box.createVerticalGlue());
    private void addDuplicatorPanel() {
        int index = oneup++;
        JComponent component = this.createDuplicate();
        JButton btnAdd = new JButton("Add");
        btnAdd.setActionCommand("" + index);
        btnAdd.addActionListener(this.addAction);
        JButton btnRemove = new JButton("Remove");
        btnRemove.setActionCommand("" + index);
        btnRemove.addActionListener(this.removeAction);
        Box box = Box.createHorizontalBox();
        box.add(component);
        box.add(Box.createHorizontalGlue());
        box.add(btnAdd);
        box.add(btnRemove);
        this.panelMap.put("" + index, box);
        fireValueChanged();
    private void fireValueChanged() {
        this.removeAll();
        this.placeComponents();
        this.repaint();
    protected void doAdd() {
        addDuplicatorPanel();
        fireValueChanged();
    protected void doRemove(String key) {
        if(this.panelMap.size() == 1) {
            return;
        JComponent comp = this.panelMap.remove(key);
        if(comp != null) {
            this.fireValueChanged();
    protected abstract JComponent createDuplicate();
    class AddAction extends AbstractAction {
        private static final long serialVersionUID = 1L;
        public void actionPerformed(ActionEvent evt) {
            doAdd();
    class RemoveAction extends AbstractAction {
        private static final long serialVersionUID = 1L;
        public void actionPerformed(ActionEvent evt) {
            JButton source = (JButton) evt.getSource();
            doRemove(source.getActionCommand());
     * @param args
    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.add(new MyDuplicatorPanel());
        f.setSize(200, 200);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setVisible(true);
    static class MyDuplicatorPanel extends DuplicatorPanel {
        private static final long serialVersionUID = 1L;
        public JComponent createDuplicate() {
            return new JLabel("Test");
}This is another class that calls the above
package sam.dnd;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.HashMap;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class HyperLinkBuilder extends JPanel {
    private static final long serialVersionUID = 1L;
     * @param args
    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.add(new HyperLinkBuilder());
        f.setSize(200, 200);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setVisible(true);
    private static HashMap<String, String> linkNameValueMap = new HashMap<String, String>();
    private static HashMap<String, String> paramNameValueMap = new HashMap<String, String>();
    private static HashMap<String, String> valueNameValueMap = new HashMap<String, String>();
    static {
        linkNameValueMap.put("Name1", "Value1");
        linkNameValueMap.put("Name2", "Value2");
        linkNameValueMap.put("Name3", "Value3");
        paramNameValueMap.put("Name1", "Value1");
        paramNameValueMap.put("Name2", "Value2");
        paramNameValueMap.put("Name3", "Value3");
        valueNameValueMap.put("Name1", "Value1");
        valueNameValueMap.put("Name2", "Value2");
        valueNameValueMap.put("Name3", "Value3");
    private String link;
    private JComboBox linkCombo;
    private DuplicatorPanel panel;
    public HyperLinkBuilder() {
        this.initComponents();
        this.placeComponents();
        this.addListeners();
    private void initComponents() {
        linkCombo = new JComboBox(linkNameValueMap.keySet().toArray());
        panel = new MyDuplicatorPanel();
    private void placeComponents() {
        this.setLayout(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridx = 0;
        gbc.gridy = 0;
        this.add(linkCombo, gbc);
        gbc.gridy++;
        gbc.fill = GridBagConstraints.BOTH;
        this.add(panel, gbc);
    private void addListeners() {
        this.linkCombo.addItemListener(new LinkSelector());
    private JPanel createNameValuePanel() {
        JComboBox nameCombo = new JComboBox(paramNameValueMap.keySet().toArray());
        JComboBox valueCombo = new JComboBox(valueNameValueMap.keySet().toArray());
        JPanel panel = new JPanel();
        panel.add(nameCombo);
        panel.add(valueCombo);
        return panel;
    private void doLinkSelected() {
        String name = (String) linkCombo.getSelectedItem();
        link = linkNameValueMap.get(name);
    public String build() {
        //TODO:
        return this.link;
    class LinkSelector implements ItemListener {
        public void itemStateChanged(ItemEvent e) {
            doLinkSelected();
    class MyDuplicatorPanel extends DuplicatorPanel {
        private static final long serialVersionUID = 1L;
        @Override
        protected JComponent createDuplicate() {
            return HyperLinkBuilder.this.createNameValuePanel();
}

Answer 1

Hey Xeon,
Replace that repaint() with revalidate. That is the trick in there.
-Sam