I don't know how to display timer when stopped

How are you all doing? I have a little problem with my code. When I stop my timer program, it will say "Done!" since I set it to "Done", but I would like to display the remaining time instead of the word "Done". Like for example if I the original time set is 4000 Seconds and I stopped at 3000 seconds I want to display the current time which is 3000 when stopping it instead of the word "Done". Can you guys help me out? I would really appreciate it.

Here's my code:

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

import javax.swing.*;
public class CountdownTimer extends JFrame  {

    JLabel promptLabel, timerLabel;
    int counter;
    JLabel tf;
    JButton button;
    Timer timer;


    public static void main(String args[]) {

        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new CountdownTimer();
            }

        });

    }


    public CountdownTimer() {

        JFrame lt = new JFrame();
            lt.getContentPane().setBackground(new Color(0, 102, 153));
            lt.setBounds(100, 100, 450, 300);
            lt.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            lt.getContentPane().setLayout(null);
            lt.setVisible(true);

        promptLabel = new JLabel("Time: ", SwingConstants.CENTER);
        promptLabel.setFont(new Font("Modern No. 20", Font.BOLD, 17));
        promptLabel.setBounds(21, 30, 210, 30);
        lt.add(promptLabel);

        tf = new JLabel("4000");
        tf.setBounds(160, 36, 40, 20);
        lt.add(tf);

        button = new JButton("Start");
        button.setFont(new Font("Modern No. 20", Font.BOLD, 11));
        button.setBounds(299, 37, 89, 23);
        lt.add(button);

        JButton btnLogout = new JButton("LOGOUT");

        btnLogout.setBackground(new Color(112, 128, 144));
        btnLogout.setFont(new Font("Trajan Pro", Font.BOLD, 17));
        btnLogout.setBounds(149, 189, 121, 36);
        btnLogout.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                 String sbutt = e.getActionCommand();

                 if(sbutt.equals("LOGOUT")) {


                     long current = counter;
                     long elapsed = current - counter;

                        timer.stop();
                        timerLabel.setText("Done!");
                        Toolkit.getDefaultToolkit().beep();
                        tf.setText(String.valueOf(elapsed));

                 }
            }
        });
        lt.getContentPane().add(btnLogout);

        timerLabel = new JLabel("Waiting...", SwingConstants.CENTER);
        timerLabel.setFont(new Font("Modern No. 20", Font.BOLD, 17));
        timerLabel.setBounds(119, 97, 176, 62);
        lt.getContentPane().add(timerLabel);

        event e =  new event();
        button.addActionListener(e);
    }
    public void actionPerformed(ActionEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }
    public void run() {
        throw new UnsupportedOperationException("Not supported yet.");
    }
    public class event implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            int count = (int)(Double.parseDouble(tf.getText()));
            timerLabel.setText("Time left: " + count);
            TimeClass tc = new TimeClass(count);
            timer = new Timer(1000, tc);
            timer.start();
        }
    }
    public class TimeClass implements ActionListener {
        int counter;
        public TimeClass(int counter) {
            this.counter= counter;
   }
        public void actionPerformed(ActionEvent tc) {
            counter--;
            if(counter >= 1) {
                timerLabel.setText("Time left: " + counter);
            }
            else {
                timer.stop();
                timerLabel.setText("Done!");
                Toolkit.getDefaultToolkit().beep();
            }
        }
    }
}

but I would like to display the remaining time instead of the word "Done".

Change timerLabel.setText("Done!"); to timerLabel.setText(counter);?

I should point out that because of it's nature, Swing Timer is not entirely accurate and you should be focusing the amount of time that has passed and not how often the timer has been called. This of course comes entirely down to how accurate you want the count to be of course, but it's worth knowing (IMHO)

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public static class TestPane extends JPanel {

        private JLabel label;
        private JButton button;

        private Timer timer;
        private long startedAt;

        public static final int RUN_TIME = 5000;

        public TestPane() {
            label = new JLabel("...");
            button = new JButton("Start");
            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridwidth = GridBagConstraints.REMAINDER;

            add(label, gbc);
            add(button, gbc);

            button.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    if (timer == null) {
                        button.setText("Stop");
                        startedAt = System.currentTimeMillis();
                        timer = new Timer(500, new ActionListener() {
                            @Override
                            public void actionPerformed(ActionEvent e) {
                                long diff = System.currentTimeMillis() - startedAt;
                                if (diff >= RUN_TIME) {
                                    label.setText("Out of time; Used: " + remainingTime() + "s; remaining " + usedTime() + "s");
                                    timer.stop();
                                    button.setText("Start");
                                } else {
                                    label.setText("Used: " + remainingTime() + "s; remaining " + usedTime() + "s");
                                }
                            }
                        });
                        label.setText("Used: " + remainingTime() + "s; remaining " + usedTime() + "s");
                        timer.start();
                    } else {
                        timer.stop();
                        long diff = System.currentTimeMillis() - startedAt;
                        label.setText("Used: " + remainingTime() + "s; remaining " + usedTime() + "s");
                        button.setText("Start");
                        timer = null;
                    }
                }
            });
        }

        public int remainingTime() {
            long diff = System.currentTimeMillis() - startedAt;
            return (int) Math.round((RUN_TIME - diff) / 1000d);
        }

        public int usedTime() {
            long diff = System.currentTimeMillis() - startedAt;
            return (int) Math.round(diff / 1000d);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(300, 200);
        }

    }

}