Quiz Code GUI

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

public class quiz extends JFrame{

  // setting up the variables for the GUI items
  private JTextField _ans1TF = new JTextField(7); // text field for Q1
  private JLabel _result = new JLabel(""); // a label to display the final result
  private JButton submitBtn = new JButton("Submit"); //a button to submit the answers

  public quiz() {
    JFrame frame = new JFrame("Quiz"); // defining a new frame for the window.


    frame.setLayout(new GridLayout(0, 3)); //using a Grid layout 0 rows 3 columns

    //adding items to the frame, when the columns in a row are full then it shall move onto the next row.
    frame.add(new JLabel("CS QUIZ"));//row 1
    frame.add(new JLabel(""));//row 1
    frame.add(new JLabel(""));//row 1

    frame.add(new JLabel("1. How many bits in a byte?"));//row 2
    frame.add(_ans1TF);//row 2
    frame.add(_result);//row 2

    //-----add more questions here...

   //-----------------------
   frame.add(new JLabel(""));//final row
   frame.add(submitBtn);//final row


   frame.pack();
   frame.setVisible(true);

   //.addActionListener links the button to the SubmitButton class, that will check the answers
   //when the submit button is clicked
   submitBtn.addActionListener(new SubmitBtnListener());
   _ans1TF.addActionListener(new SubmitBtnListener());
  }

  //code that runs when the button is clicked
  class SubmitBtnListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            String a1Str = _ans1TF.getText();
            if (a1Str.equals("8")){
                _result.setText("✓");//changes the result label to ✓ if the answer is correct
            } else{
                _result.setText("X");//changes the result label to X if the answer is incorrect
            }

        }
    }


}