I want to display what is typed in the textfield when a button is clicked

import java.awt.*;
import java.awt.event.*;

public class Q7 {
    Q7(){
       Frame f= new Frame("Calculator");
       TextField txt1 = new TextField(15);
       Button b = new Button("Submit");
       Label lbl = new Label();
       
       b.addActionListener(new ActionListener(){
           public void actionPerformed(ActionEvent e){
               txt1.addItemListener(new ItemListener(){
                   @Override
                   public void itemStateChanged(ItemEvent e){
                       String s=txt1.getSelectedItem();
                        l2.setText(s);
                   }
               });
           }
       });
       
       f.addWindowListener(new WindowAdapter(){
           public void windowClosing(WindowEvent we){
            System.exit(0);
           }
       });
       f.add(txt1);
       f.add(b);
       f.add(lbl);
       
       f.setLayout(new FlowLayout());
       f.setSize(400,300);
       f.setVisible(true);
       
       
    }   
    public static void main(String[] args){
      Q7 f = new Q7();   
    }
}