MouseMover.java

import java.awt.*;
import java.time.LocalDateTime;

public class MouseMover {
    public static final int PAUSE = 20000;

    public static void main(String... args) throws Exception {

        int limit = args.length == 0 ? 24 : Integer.parseInt(args[0]);
        System.out.println("Time limit: " + limit);
        
        Robot robot = new Robot();
        int increment = 1;
        while (LocalDateTime.now().getHour() < limit) {
            increment *= -1;
            Point p = MouseInfo.getPointerInfo().getLocation();
            robot.mouseMove(p.x + increment, p.y + increment);
            Thread.sleep(PAUSE);
        }

    }
}