AutoClicker

package com.autoclicker;

import java.awt.Dimension;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.event.InputEvent;
import java.util.Random;

import javax.swing.JFrame;

public class AutoClicker extends javax.swing.JFrame {
    private static final long serialVersionUID = 4035771675111011526L;

    private static int CLICK_INTERVAL = 40 * 1000; // 40 sec
    // private static int CLICK_INTERVAL = 5000; // 5 sec
    private Clicker clicker;

    public AutoClicker() {
        initComponents();
        setStartEnabled(true);
        clicker = null;
    }

    private void setStartEnabled(boolean state) {
        startButton.setEnabled(state);
        stopButton.setEnabled(!state);
    }

    private void initComponents() {
        startButton = new javax.swing.JButton();
        stopButton = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        startButton.setText("Start");
        startButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                startButtonActionPerformed(evt);
            }
        });

        stopButton.setText("Stop");
        stopButton.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                stopButtonActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(
                getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(layout.createParallelGroup(
                javax.swing.GroupLayout.Alignment.LEADING).addGroup(
                layout.createSequentialGroup()
                        .addContainerGap()
                        .addComponent(startButton,
                                javax.swing.GroupLayout.DEFAULT_SIZE, 250,
                                Short.MAX_VALUE)
                        .addGap(28, 28, 28)
                        .addComponent(stopButton,
                                javax.swing.GroupLayout.PREFERRED_SIZE, 239,
                                javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addContainerGap()));
        layout.setVerticalGroup(layout
                .createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(
                        layout.createSequentialGroup()
                                .addContainerGap()
                                .addGroup(
                                        layout.createParallelGroup(
                                                javax.swing.GroupLayout.Alignment.LEADING,
                                                false)
                                                .addComponent(
                                                        stopButton,
                                                        javax.swing.GroupLayout.DEFAULT_SIZE,
                                                        185, Short.MAX_VALUE)
                                                .addComponent(
                                                        startButton,
                                                        javax.swing.GroupLayout.DEFAULT_SIZE,
                                                        javax.swing.GroupLayout.DEFAULT_SIZE,
                                                        Short.MAX_VALUE))
                                .addContainerGap(
                                        javax.swing.GroupLayout.DEFAULT_SIZE,
                                        Short.MAX_VALUE)));

        pack();
    }// </editor-fold>

    private void startButtonActionPerformed(java.awt.event.ActionEvent evt) {
        startButton.setEnabled(false);
        stopButton.setEnabled(false);

        clicker = new Clicker();
        clicker.start();

        setStartEnabled(false);
    }

    private void stopButtonActionPerformed(java.awt.event.ActionEvent evt) {
        startButton.setEnabled(false);
        stopButton.setEnabled(false);
        clicker.killThread();
        clicker = null;
        setStartEnabled(true);
    }

    public static void main(String args[]) {
        AutoClicker frame = new AutoClicker();
        frame.setLocationRelativeTo(null);
        frame.setResizable(false);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    // Variables declaration - do not modify
    private javax.swing.JButton startButton;
    private javax.swing.JButton stopButton;

    // End of variables declaration

    class Clicker extends Thread {
        private Robot robot;
        private Random random;
        private int clickHeight;
        private int clickWidth;
        private boolean toContinue;
        private int randomSlack;

        public Clicker() {
            try {
                robot = new Robot();
                random = new Random();

                Dimension screenSize = Toolkit.getDefaultToolkit()
                        .getScreenSize();
                int screenHeight = (int) (screenSize.getHeight() + 1e-7);
                int screenWidth = (int) (screenSize.getWidth() + 1e-7);

                int minSlack = Math.min(screenHeight, screenWidth);

                randomSlack = minSlack / 8;

                clickHeight = screenHeight / 2;
                clickWidth = screenWidth / 2;
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }

        @Override
        public void run() {
            toContinue = true;

            while (toContinue) {
                try {
                    Thread.sleep(CLICK_INTERVAL);

                    if (toContinue) {
                        for (int i = 0; i < 3 && toContinue; i++) {
                            robot.mouseMove(clickWidth + getRandomSlack(),
                                    clickHeight + getRandomSlack());
                            robot.mousePress(InputEvent.BUTTON1_MASK);
                            robot.mouseRelease(InputEvent.BUTTON1_MASK);
                            Thread.sleep(100);
                        }
                        // System.out.println("Clicked");
                    }
                } catch (InterruptedException ex) {
                }
            }
        }

        private int getRandomSlack() {
            return random.nextInt(randomSlack) - (randomSlack / 2);
        }

        public void killThread() {
            toContinue = false;
            this.interrupt();
        }
    }
}