2

package Practice;

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

public class Main {
    private static int cnt = 3;
    public static void main(String[] args) {
        JFrame fr = new JFrame("Run!");
        fr.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        fr.setSize(250, 100);

        JLabel label = new JLabel();
        JButton button = new JButton("Click!");

        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if( cnt == 3 ) {
                    cnt = 2;
                    label.setText("3...");
                }
                else if( cnt == 2 ) {
                    cnt = 1;
                    label.setText("2...");
                }
                else if( cnt == 1 ) {
                    cnt = 0;
                    label.setText("1...");
                }
                else if( cnt == 0 ) {
                    cnt = 3;
                    label.setText("GO!");
                }
            }
        });

        Container c = fr.getContentPane();
        c.setLayout(new FlowLayout());
        c.add(label);
        c.add(button);

        fr.setVisible(true);
    }