stop():

The stop() method is called whenever a web browser leaves the HTML document containing the applet - when it goes to another page, for instance. When stop() is called, the applet is possibly Running . You should use stop() to suspend threads that don't required to run when the applet is not visible. You could restart them when start() is called if the user returns to the page.

destroy():

The destroy() method is called when the environment determines which your applet required to be removed completely from memory. At the point, you should free up any resources the applet might be using. The stop() method is always called before destroy().