How to populate the second combo box by depending on the selection in 1st?

Question

I have two combo boxes, both of data in the lists come from the database. The list in the second will be changed when the selection is changed in the first one. I am trying to do query again in the ActionPerform function, unfortunately the list in second one doesn't change.
I am learning Swing now, I really appreciate for any suggestions!
Thanks

Answer 1

camickr,
I have another question for the tab pane. Now I have to remove the tab and add tab for updating the tab pane. I wonder if there is other way to do it. I really appreciate your help!
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import java.net.URL;
import java.util.Iterator;
import java.util.List;
import java.util.StringTokenizer;
public class test_tabpane extends JPanel implements ActionListener {
     private JPanel MainPane;
     private JComboBox combobox2;
     private JTabbedPane TabbedPane;
     private JComponent panel1;
     private JComponent panel2;
     private String [] resources ={"ZZAA", "ZZAB", "ZZAC", "ZZAD"};
     private String selected_resource = "";
     public test_tabpane() {
          MainPane = new JPanel();
        MainPane.setOpaque(true);
        MainPane.setPreferredSize(new Dimension(600, 70));
        MainPane.setBorder(BorderFactory.createRaisedBevelBorder());
        combobox2 = new JComboBox(resources);
        combobox2.addActionListener(this);
        MainPane.add(combobox2);
        add(MainPane);
        UIManager.put("TabbedPane.tabInsets", new Insets(5,5,5,5));
        TabbedPane = new JTabbedPane();
        panel1 = makeTextPanel(resources[0]);
        TabbedPane.addTab("Language/Notes", panel1);
        panel2= makeTextPanel(resources[0]);
        TabbedPane.addTab("Relations/Coverage", panel2);
        TabbedPane.setPreferredSize(new Dimension(600, 340));
        TabbedPane.setFont(new Font("ariel", Font.BOLD, 11));
        TabbedPane.setSize(600, 340);
        add(TabbedPane);
     protected JComponent makeTextPanel(String text) {
        JPanel panel = new JPanel(false);
        JLabel filler = new JLabel(text);
        filler.setHorizontalAlignment(JLabel.CENTER);
    //    panel.setLayout(new GridLayout(1, 1));
        panel.add(filler);
        return panel;
     public void actionPerformed(ActionEvent e) {
               JComboBox cb = (JComboBox)e.getSource();
               if ("comboBoxChanged".equals(e.getActionCommand()))
               //   if ("comboBoxEdited".equals(e.getActionCommand()))
               //     System.out.println("in action:" + (String)cb.getSelectedItem());
                    String selected_string = (String)cb.getSelectedItem();
                    StringTokenizer st = new StringTokenizer(selected_string, "|");
                    selected_resource = st.nextToken();
                    updateTabbedPanes(selected_resource);
    protected void updateTabbedPanes(String selected_string) {
         panel1 = makeTextPanel(selected_string + " in Language/Notes");
         int index = TabbedPane.indexOfTab("Language/Notes");
         TabbedPane.remove(index);
         TabbedPane.insertTab("Language/Notes", null, panel1, "", index);
         panel2 = makeTextPanel(selected_string + " in Relations/Coverage");
         index = TabbedPane.indexOfTab("Relations/Coverage");
         TabbedPane.remove(index);
         TabbedPane.insertTab("Relations/Coverage", null, panel2, "", index);
    * Create the GUI and show it.  For thread safety,
    * this method should be invoked from the
    * event-dispatching thread.
   private static void createAndShowGUI() {
           JFrame.setDefaultLookAndFeelDecorated(false);
       //Create and set up the window.
         JFrame frame = new JFrame("test");
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       //Create and set up the content pane.
       JComponent ContentPane = new test_tabpane();
       ContentPane.setOpaque(true); //content panes must be opaque
       frame.setContentPane(ContentPane);
       //centers a frame onscreen // it is a problem for wide screen
       //   frame.setLocationRelativeTo(null);
       frame.setLocation(300, 120);
       frame.setSize(1024, 768);
       frame.setExtendedState(java.awt.Frame.MAXIMIZED_BOTH);
       //Display the window.
      frame.pack();
       frame.setVisible(true);
      * @param args
      * This is main function.
     public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
}