Serializing a Panel...

Question

Hi there
I want to save the content of the programmatically buttons in the Panel. However, sometimes I got the following exception and I really can't work out why. Please help I really can't work it out.
java.io.NotSerializableException: javax.swing.DefaultPopupFactory      at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1148)      at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366)      at java.io.ObjectOutputStream.outputClassFields(ObjectOutputStream.java:1827)      at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:480)      at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1214)      at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366)      at java.awt.Window.writeObject(Window.java:1048)      at java.lang.reflect.Method.invoke(Native Method)      at java.io.ObjectOutputStream.invokeObjectWriter(ObjectOutputStream.java:1864)      at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1210)      at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366)      at java.io.ObjectOutputStream.outputClassFields(ObjectOutputStream.java:1827)      at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:480)      at java.io.ObjectOutputStream.outputObject(ObjectOutputStream.java:1214)      at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:366)      at Assignment1$5.actionPerformed(Assignment1.java:142)      at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1450)      at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1504)      at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:378)      at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:250)      at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:216)      at java.awt.Component.processMouseEvent(Component.java:3715)      at java.awt.Component.processEvent(Component.java:3544)      at java.awt.Container.processEvent(Container.java:1164)      at java.awt.Component.dispatchEventImpl(Component.java:2593)      at java.awt.Container.dispatchEventImpl(Container.java:1213)      at java.awt.Component.dispatchEvent(Component.java:2497)      at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:2451)      at java.awt.LightweightDispatcher.processMouseEvent(Container.java:2216)      at java.awt.LightweightDispatcher.dispatchEvent(Container.java:2125)      at java.awt.Container.dispatchEventImpl(Container.java:1200)      at java.awt.Window.dispatchEventImpl(Window.java:926)      at java.awt.Component.dispatchEvent(Component.java:2497)      at java.awt.EventQueue.dispatchEvent(EventQueue.java:339)      at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:131)      at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:98)      at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)      at java.awt.EventDispatchThread.run(EventDispatchThread.java:85)
My source code.
import java.awt.*;
import javax.swing.*;
import java.io.Serializable;
public interface AbstractPanel extends Serializable{
     public void addButton(String s);
     public void updateButton(String s);
     public void deleteButton();
     public void setPanel(Container content, JPanel panel3);
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.*;
import java.util.*;
public class BorderLayoutPanel extends JPanel implements AbstractPanel {
     private Assignment1 parent;
     protected JComboBox comboBox = new JComboBox();
     private Vector buttons = new Vector();
     public BorderLayoutPanel(Assignment1 pt) {
          super();
          parent = pt;          
          setLayout(new BorderLayout());
          TitledBorder title1 = BorderFactory.createTitledBorder("Subject JPanel");
          setBorder(title1);                    
          comboBox.addItem(BorderLayout.NORTH);
          comboBox.addItem(BorderLayout.SOUTH);
          comboBox.addItem(BorderLayout.WEST);
          comboBox.addItem(BorderLayout.EAST);
          comboBox.addItem(BorderLayout.CENTER);          
     public void addButton(String s) {
          JButton newb = new JButton(s);
          buttons.add(newb);
          newb.addActionListener(new ActionListener() {
               public void actionPerformed(ActionEvent ev) {
                    parent.clicked = (JButton) ev.getSource();
                    parent.text.setText(parent.clicked.getText());
                    parent.update.setEnabled(true);
                    parent.delete.setEnabled(true);
          add(newb, ((String) comboBox.getSelectedItem()) );
          validate();
          repaint();
     public void updateButton(String s) {
          remove(parent.clicked);
          parent.clicked.setText(s);
          add(parent.clicked, ((String) parent.comboBox.getSelectedItem()) );
          parent.update.setEnabled(false);
          parent.delete.setEnabled(false);
          validate();
          repaint();
     public void deleteButton() {
          remove(parent.clicked);
          parent.update.setEnabled(false);
          parent.delete.setEnabled(false);
          validate();
          repaint();
     public void setPanel(Container content, JPanel panel3) {
          panel3.setLayout(new BorderLayout());
          panel3.add(comboBox, BorderLayout.WEST);
          content.validate();
          content.repaint();     
Thank you for any suggest and advice!
Edmond

Answer 1

Hi there,
I have found that after I click on the JComboBox, I will get the exception. Does anyone know if there is any special about serializing the JComboBox? Or, is there a bug in it?
Thank you!