Life Cycle of an Applet


Four methods in the Applet class give you the framework on which you build any serious applet:

init: This method is intended for whatever initialization is needed for your applet. It is called after the param tags inside the applet tag have been processed.

start: This method is automatically called after the browser calls the init method. It is also called whenever the user returns to the page containing the applet after having gone off to other pages.

stop: This method is automatically called when the user moves off the page on which the applet sits. It can, therefore, be called repeatedly in the same applet.

destroy: This method is only called when the browser shuts down normally. Because applets are meant to live on an HTML page, you should not normally leave resources behind after a user leaves the page that contains the applet.

paint: Invoked immediately after the start() method, and also any time the applet needs to repaint itself in the browser. The paint() method is actually inherited from the java.awt.

Applet Life Cycle Example

/*
        Applet Life Cycle Example
        This java example explains the life cycle of Java applet.
*/
import java.applet.Applet;
import java.awt.Graphics;
 
/*
 * Applet can either run by browser or appletviewer application.
 * Define <applet> tag within comments as given below to speed up
 * the testing.
 */
 
/*
<applet code="AppletLifeCycleExample" width=100 height=100>
</applet>
*/
 
public class AppletLifeCycleExample extends Applet{
       
        /*
         * init method is called first.
         * It is used to initialize variables and called only once.
         */
        public void init() {
                super.init();
        }
       
        /*
         * start method is the second method to be called. start method is
         * called every time the applet has been stopped.
         */
        public void start() {
                super.start();
        }
       
        /*
         * stop method is called when the the user navigates away from
         * html page containing the applet.
         */
        public void stop() {
                super.stop();
        }
       
        /* paint method is called every time applet has to redraw its
         * output.
         */
        public void paint(Graphics g) {
                super.paint(g);
        }
       
        /*
         * destroy method is called when browser completely removes
         * the applet from memeory. It should free any resources initialized
         * during the init method.
         */
        public void destroy() {
                super.destroy();
        }
 
}

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