U'd probably want the code.. it's too long.. so i've snipped parts out of it:
import javax.swing.*;
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
public class ApplicationCentre extends Applet
{ private JButton inputButton, admitButton, displayButton, submitButton;
private JPanel buttonsPanel, defaultPanel, inputPanel, admitPanel, displayPanel, rightPanel;
private JPanel textFieldPanel;
private JList universitiesList;
private JTextArea inputTextArea;
private JLabel nameLabel, averageLabel, storageAmount;
private JTextField studentNameTextfield, studentAverageTextfield;
private JComboBox studentsComboBox;
private int count, capacity;
private Student[] studentArray;
public static final String[] UNIVERSITIES = {"Toronto", "York", "Western", "Brock", "Guelph", "Waterloo", "McGill", "Concordia", "Laval", "Macmaster"};
public void init()
{ int size = Integer.parseInt(JOptionPane.showInputDialog("Enter size of database"

);
capacity = size;
studentArray = new Student[capacity];
count = 0;
setLayout(new BorderLayout());
// JPanel for action listener buttons (input, admit, display)
buttonsPanel = new JPanel(new GridLayout(3,1));
inputButton = new JButton("Input"

;
inputButton.addActionListener(new inputButtonListener());
admitButton = new JButton("Admit"

;
admitButton.addActionListener(new admitButtonListener());
displayButton = new JButton("Display"

;
displayButton.addActionListener(new displayButtonListener());
buttonsPanel.add(inputButton);
buttonsPanel.add(admitButton);
buttonsPanel.add(displayButton);
// constructs the defaultPanel, inputPanel, admitPanel, & displayPanel
defaultPanel();
inputPanel();
admitPanel();
rightPanel = new JPanel(new CardLayout());
rightPanel.add(defaultPanel, "DEFAULT"

;
rightPanel.add(inputPanel, "INPUT"

;
rightPanel.add(admitPanel, "ADMIT"

;
add(buttonsPanel, BorderLayout.WEST);
add(rightPanel, BorderLayout.CENTER);
}
private void defaultPanel()
{ // JPanel for default panel
}
private void inputPanel()
{ // JPanel for inputPanel
submitButton.addActionListener(new submitButtonListener());
}
private void admitPanel()
{ // JPanel for admitPanel
GridBagLayout gridbag = new GridBagLayout();
GridBagConstraints constraint = new GridBagConstraints();
admitPanel = new JPanel(gridbag);
studentsComboBox = new JComboBox();
admitPanel.add(studentsComboBox);
}
private class inputButtonListener implements ActionListener
{ public void actionPerformed(ActionEvent event)
{ CardLayout cl = (CardLayout)(rightPanel.getLayout());
cl.show(rightPanel, "INPUT"

;
}
}
private class submitButtonListener implements ActionListener
{ public void actionPerformed(ActionEvent event)
{ studentsComboBox.addItem(name);
}
}
private class admitButtonListener implements ActionListener
{ public void actionPerformed(ActionEvent event)
{ CardLayout cl = (CardLayout)(rightPanel.getLayout());
cl.show(rightPanel, "ADMIT"

;
System.out.println(studentsComboBox.getItemCount());
System.out.println(studentsComboBox.isVisible());
}
}
private class displayButtonListener implements ActionListener
{ public void actionPerformed(ActionEvent event)
{
}
}
}