Example of using Swing JComboBox

JComboBox and ActionListener

package javamyframe;

import java.awt.BorderLayout;
import java.awt.Label;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

/**
 * @web http://java-buddy.blogspot.com/
 */
public class JavaMyFrame extends JFrame
    implements ActionListener{

    JComboBox jComboBox1;
    JTextField textField2;
    Label labelInfo;
    JButton buttonAccept;
    
    static final String DayOfWeek[] = {
        "Monday",
        "Tuesday",
        "Wednesday",
        "Thursday",
        "Friday"};

    public static void main(String[] args) {
        
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }

    private static void createAndShowGUI() {
        JavaMyFrame myFrame = new JavaMyFrame();

        myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        myFrame.prepareUI();

        myFrame.pack();
        myFrame.setVisible(true);
    }
    
    private void prepareUI(){
        
        JPanel panel = new JPanel();
        panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
        
        jComboBox1 = new JComboBox(DayOfWeek);
        jComboBox1.setSelectedIndex(1);
        jComboBox1.addActionListener(this);
        
        textField2 = new JTextField(20);
        labelInfo = new Label();
        panel.add(jComboBox1);
        panel.add(textField2);
        panel.add(labelInfo);
        
        buttonAccept = new JButton("Accept");
        buttonAccept.addActionListener(this);
        
        getContentPane().add(panel, BorderLayout.CENTER);
        getContentPane().add(buttonAccept, BorderLayout.PAGE_END);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        textField2.setText((String)jComboBox1.getSelectedItem());
        
        if(e.getSource() == jComboBox1){
            labelInfo.setText("by jComboBox1");
        }else if(e.getSource() == buttonAccept){
            labelInfo.setText("by buttonAccept");
        }else{
            labelInfo.setText("unknow source");
        }
    }

}