Red Ball

import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Random;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.Timer;

public class QS extends JFrame {
  private static final long serialVersionUID = 1L;

  public static void main(String[] args) {
    new QS();
  }
  private final JButton start;
  private final JButton action;
  private final Timer[] timer = new Timer[2];
  private final Random r;
  private final int millisec;
  private final QS self;

  public QS() {
    setTitle("QS");
    setSize(new Dimension(300, 300));
    setLayout(new FlowLayout());
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    r = new Random();
    self = this;
    millisec = 2000 + r.nextInt(10000);
    timer[0] = new Timer(millisec, new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent e) {
        timer[1].start();
        timer[0].stop();
        timer[0].setDelay(2000 + r.nextInt(10000));
        paint();
        action.setEnabled(true);
      }
    });
    timer[1] = new Timer(1500, new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent e) {
        timer[1].stop();
        JOptionPane.showMessageDialog(self, "FAIL");
        clear();
        start.setEnabled(true);
        action.setEnabled(false);
      }
    });
    start = new JButton("Start");
    start.addMouseListener(new MouseAdapter() {
      @Override
      public void mouseClicked(MouseEvent e) {
        start.setEnabled(false);
        timer[0].start();
      }
    });
    add(start);
    action = new JButton("Action");
    action.addMouseListener(new MouseAdapter() {
      @Override
      public void mouseClicked(MouseEvent e) {
        timer[0].stop();
        timer[1].stop();
        JOptionPane.showMessageDialog(self, "SUCCESS");
        clear();
        start.setEnabled(true);
        action.setEnabled(false);
      }
    });
    action.setEnabled(false);
    add(action);
    setVisible(true);
  }

  private void clear() {
    Graphics g = getGraphics();
    g.setColor(getBackground());
    g.fillRect(100, 100, 100, 100);
  }

  private void paint() {
    Graphics g = getGraphics();
    g.setColor(Color.RED);
    g.fillOval(100, 100, 100, 100);
  }
}