Thread: JComboBox and Textfield

Hello, I am creating a JComboBox and textfield. When ever the user selects an item from the ComboBox its supposed to show up in the textfield. Right now, if you select one item, it will show up in the textfield, select another item and it take out the previous item and show the new one. I want to make it so that all of the user choices will be in the textfield.

My code so far:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
 
public class ComboBox{
	JComboBox combo;
	JTextField txt;
	public static void main(String[] args) {
		ComboBox b = new ComboBox();
	}
 
	public ComboBox(){
		String course[] = {"BCA","MCA","PPC","CIC"};
		JFrame frame = new JFrame("Creating a JComboBox Component");
		JPanel panel = new JPanel();
		combo = new JComboBox(course);
		combo.setBackground(Color.gray);
		combo.setForeground(Color.red);
		txt = new JTextField(10);
		panel.add(combo);
		panel.add(txt);
		frame.add(panel);
		combo.addItemListener(new ItemListener(){
			public void itemStateChanged(ItemEvent ie){
				String str = (String)combo.getSelectedItem();
				txt.setText(str);
			}
		});
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(400,400);
		frame.setVisible(true);
	}
}