my{} JAVA basketball app

package basketball;
import java.awt.event.ActionEvent;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;
public class Basketball extends JFrame implements ActionListener{
    JLabel lbl = new JLabel("Select a Team");
    JComboBox cmb = new JComboBox();
    JTextField txt = new JTextField(30);
    FlowLayout fl = new FlowLayout(FlowLayout.CENTER,20,30);
    public Basketball(){
        super("Team Select");
        setLayout(fl);
        setSize(400,200);
        setVisible(true);
        add(lbl);
        add(cmb);
        cmb.addItem("LAKERS");
        cmb.addItem("CELTICS");
        cmb.addItem("KNICKS");
        cmb.addItem("ROCKETS");
        cmb.addItem("HEAT");
        cmb.addItem("SPURS");
        cmb.addActionListener(this);
        cmb.setEditable(false);
        add(txt);
        txt.addActionListener(this);
        txt.setEditable(false);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
    }
    public static void main(String []args){
        Basketball jbb = new Basketball();
}
   
    public void actionPerformed(ActionEvent ex) {
        int selected = cmb.getSelectedIndex();
        if(ex.getSource() == cmb){
            if (selected == 0)
                txt.setText("You Chose : LOS ANGELES LAKERS! ");
            else if (selected == 1)
                txt.setText("You Chose : BOSTON CELTICS! ");
            else if (selected == 2)
                txt.setText("You Chose :NEW YORK KNICKS!  ");
            else if (selected == 3)
                txt.setText("You Chose : HOUSTON ROCKETS! ");
            else if (selected == 4)
                txt.setText("You Chose : MIAMI HEAT! !!");
            else if (selected == 5)
                txt.setText("You Chose : SAN ANTONIO SPURS! ");
        }
    }
}