Java tutorial
import java.awt.FlowLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JProgressBar; import javax.swing.Timer; public class Main { public static void main(String[] args) { final Timer timer; final JProgressBar progressBar = new JProgressBar(); final JButton button = new JButton("Start"); JFrame f = new JFrame(); f.setLayout(new FlowLayout()); f.add(progressBar); f.add(button); ActionListener updateProBar = new ActionListener() { public void actionPerformed(ActionEvent actionEvent) { int val = progressBar.getValue(); if (val >= 100) { // timer.stop(); button.setText("End"); return; } progressBar.setValue(++val); } }; timer = new Timer(50, updateProBar); button.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { if (timer.isRunning()) { timer.stop(); button.setText("Start"); } else if (button.getText() != "End") { timer.start(); button.setText("Stop"); } } }); f.pack(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setResizable(false); f.setLocationRelativeTo(null); f.setVisible(true); } }