At work we have a big TV screen with a build status being displayed. The desktop support team had a large lead time on changing the settings to stop it locking the machine every 5 minutes. This was the temporary workaround.

The java.awt.Robot has a few other interesting methods like taking screenshots, getting the colour under your cursor and clicking the mouse.

This code has no dependencies.

import java.awt.Robot;
import java.util.Random;

public class MouseMover {
    public static final int FIVE_SECONDS = 5000;
    public static final int MAX_Y = 400;
    public static final int MAX_X = 400;

    public static void main(String... args) throws Exception {
        Robot robot = new Robot();
        Random random = new Random();
        while (true) {
            robot.mouseMove(random.nextInt(MAX_X), random.nextInt(MAX_Y));
            Thread.sleep(FIVE_SECONDS);
        }
    }
}

I’ve compiled a version using Java7 which you can download and use right away.