ellow,

I want to make a code where you have 3 buttons(1,2,3) and you have to press the buttons in a correct order to open the vault. and the code you entered is shown in a textfield the code is 3321. however i am only able to get one letter every time on the screen now i know why that is and that what i did is wrong, however i do not know the correct way...obviously.
so i was wondering if someone is kind enough to help me
here is the code:
Code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class MyFrame extends JFrame implements ActionListener
{
  private JButton b1, b2, b3, b4;
  private JLabel lab1, lab2;
  private JTextField tfUit;
  private final String wachtwoord = "3321";


          public MyFrame()
                 {

                          setLayout(new FlowLayout());
  
                          lab1 = new JLabel  ("raad de geheime code");
                          add(lab1);

                          b1 = new JButton("1");
                          add(b1);
                          b1.addActionListener(this);
                          
                          b2 = new JButton("2");
                          add(b2);
                          b2.addActionListener(this);
                          
                          b3 = new JButton("3");
                          add(b3);
                          b3.addActionListener(this);
                          
                           tfUit = new JTextField(8);
                           add(tfUit);
  
                          lab2 = new JLabel("hier komt de uitvoer");
                          add(lab2);
                          
                          b4 = new JButton("clear");
                          add(b4);
                          b4.addActionListener(this);
  
                           setSize(180, 250);
                           setVisible(true);
                           setDefaultCloseOperation(EXIT_ON_CLOSE);

                 }
          public void actionPerformed(ActionEvent event) 
          {
            String s = tfUit.getText();
                     if (s.equals(wachtwoord) )
                      {
                        lab2.setText("Yes! geraden");
                      }
                      else
                      {
                        lab2.setText("de kluis blijft dicht");
                      }


		if (event.getSource() == b4) 
                {
			lab2.setText("hier komt de uitvoer");
			tfUit.setText("");
		}
		if (event.getSource() == b1)
                {
			tfUit.getText();
			tfUit.setText("1");
		}
		if (event.getSource() == b2) 
                {
			tfUit.getText();
			tfUit.setText("2");
		}
		if (event.getSource() == b3) 
                {
			tfUit.getText();
			tfUit.setText("3");
                }


           }
}

and this is the main:
Code:
public class Main
{
  public static void main(String [] args)
{
   MyFrame Frame = new MyFrame();

}
}