jcheckbox control and associated event

package checkbox_control_and_event;

import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.*;

public class Checkbox_control_and_event extends JFrame implements ItemListener {

    JCheckBox jc1, jc2, jc3;
    JTextField jt;

    public Checkbox_control_and_event() {
        jt = new JTextField(40);
        jc1 = new JCheckBox("c++");
        jc2 = new JCheckBox("java");
        jc3 = new JCheckBox("c");
        add(jc1);
        add(jc2);
        add(jc3);
        add(jt);
        setLayout(null);
        jc1.setBounds(20, 20, 50, 30);
        jc2.setBounds(80, 20, 50, 30);
        jc3.setBounds(140, 20, 50, 30);
        jt.setBounds(20, 80, 120, 40);
        jc1.addItemListener(this);
        jc2.addItemListener(this);
        jc3.addItemListener(this);
    }

    @Override
    public void itemStateChanged(ItemEvent e) {
        if (e.getSource() == jc1)
        {
            jc3.setSelected(false);
           jc2.setSelected(false);
            jt.setText(jc1.getText());
        }
        else if (e.getSource() == jc2)
        {
            jc1.setSelected(false);
            jc3.setSelected(false);
            jt.setText(jc2.getText());
        }
        else if(e.getSource()==jc3)
        {
            jc1.setSelected(false);
            jc2.setSelected(false);
            jt.setText(jc3.getText());
        }
    }

    public static void main(String[] args) {
        Checkbox_control_and_event c = new Checkbox_control_and_event();
        c.setVisible(true);
        c.setSize(400, 400);
    }
}