Help needed to get my GUI to work

I'm making my first bigger Java application and I'm having some
trouble getting the GUI to work.

I'm trying to use the MigLayout to make a form with label
textfield pairs to get settings from the user.

The bigger GUI picture is frame that has cardlayout. SettingPanel
is one of the cards and this works just fine.
In the SettingPanel I want to choose what to display according to
the combobox value. If MySQL is selected then it will show MySQL
labels and textboxes.

Currently the SettingPanel only displays the combobox and nothing
else. I can select MySQL and SQLite from it but neither has any
visible effect.

-- code --

package quotedb;

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import net.miginfocom.swing.MigLayout;

class SettingPanel extends JPanel {

     private static final long serialVersionUID = 1L;
     private final static String OPTION_MYSQL = "MySQL";
     private final static String OPTION_SQLITE = "SQLite";

     // Labels and textfields for MySQL
     private JTextField mysqlUrlTxt,
     mysqlDBNameTxt,mysqlDriverTxt;
     private JTextField mysqlUsernameTxt, mysqlPasswordTxt;
     private JLabel mysqlUrlLbl, mysqlDBNameLbl, mysqlDriverLbl;
     private JLabel mysqlUsernameLbl, mysqlPasswordLbl;

     // Labels and textfields for SQLite
     private JTextField sqliteUrlTxt, sqliteDBNameTxt,
     sqliteDriverTxt;
     private String activeEngine;
     private Controller myController;
     private JPanel cards;

    public SettingPanel(Controller controllerIn) {
        try {
            myController = controllerIn;
            jbInit();
        } catch (Exception exception) {
            exception.printStackTrace();
        }
    }

    /**
     * Component initialization.
     *
     * @throws java.lang.Exception
     */
    private void jbInit() throws Exception {

         // init engine
         activeEngine = new String("none");

         // create cards where to store all database options
        cards = new JPanel(new CardLayout());
        JPanel card_mysql = new JPanel(new MigLayout("fill, insets
10, gap 2"));
        JPanel card_sqlite = new JPanel(new MigLayout("fill,
insets 10, gap 2"));

        // create components for MySQL
        mysqlUrlTxt = new JTextField(30);
        mysqlDBNameTxt = new JTextField(30);
        mysqlDriverTxt = new JTextField(30);
        mysqlUsernameTxt = new JTextField(30);
        mysqlPasswordTxt = new JTextField(30);

        // add components to card
        card_mysql.add(new JLabel("Database name:"), "gap
        unrelated");
        card_mysql.add(mysqlDBNameTxt, "wrap");
        card_mysql.add(new JLabel("Username:"), "gap unrelated");
        card_mysql.add(mysqlUsernameTxt, "wrap");
        card_mysql.add(new JLabel("Password:"), "gap unrelated");
        card_mysql.add(mysqlPasswordTxt, "wrap");
        card_mysql.add(new JButton("Save"));

        // create components for SQLite
        sqliteUrlTxt = new JTextField(30);
        sqliteDBNameTxt = new JTextField(30);

        // add components to card
        card_sqlite.add(new JLabel("Database name"), "gap
        unrelated");
        card_sqlite.add(sqliteDBNameTxt, "wrap");
        card_sqlite.add(new JButton("Save"));

        // add cards to panel
        JPanel comboBoxPane = new JPanel();
        String comboBoxItems[] = { OPTION_MYSQL, OPTION_SQLITE };
        JComboBox cb = new JComboBox(comboBoxItems);
        cb.setEditable(false);
        cb.addItemListener(new ItemListener()
             {
                  public void itemStateChanged(ItemEvent evt)
                       {
                            activeEngine = (String)evt.getItem();
                            CardLayout cl =
(CardLayout)(cards.getLayout());
                            cl.show(cards, activeEngine);
                            System.out.println("Changing card!");
                       }
             });

        comboBoxPane.add(cb);
        add(comboBoxPane, BorderLayout.PAGE_START);
        add(cards, BorderLayout.CENTER);
    }

     protected String getDBEngine() {
          return activeEngine;
     }

    protected String getDBName() throws NullPointerException {

         if (activeEngine.equals("MySQL")) {
              return mysqlDBNameTxt.getText();
         }
         else if (activeEngine.equals("SQLite")) {
              return sqliteDBNameTxt.getText();
         }
         return null;
    }

    protected String getUsername() throws NullPointerException {

         if (activeEngine.equals("MySQL")) {
              return mysqlUsernameTxt.getText();
         }
         return null;
    }

    protected String getPassword() throws NullPointerException {

         if (activeEngine.equals("MySQL")) {
              return mysqlPasswordTxt.getText();
         }
         return null;
    }

    protected void setDBName(String DBName) {

         if (activeEngine.equals("MySQL")) {
              mysqlDBNameTxt.setText(DBName);
         }
         else if (activeEngine.equals("SQLite")) {
              sqliteDBNameTxt.setText(DBName);
         }
    }

    protected void setUsername(String username) {

         if (activeEngine.equals("MySQL")) {
              mysqlUsernameTxt.setText(username);
         }
    }

    protected void setPassword(String password) {

         if (activeEngine.equals("MySQL")) {
              mysqlPasswordTxt.setText(password);
         }
    }

}