Applets

Applets

•       An applet is a program written in the Java programming language that can be included in an HTML page, much in the same way an image is included in a page.

•       When you use a Java technology-enabled browser to view a page that contains an applet, the applet's code is transferred to your system and executed by the browser's Java Virtual Machine (JVM).

Life Cycle

Applet runs in the browser and its lifecycle method are called by JVM when it is loaded and destroyed. Here are the lifecycle methods of an Applet:

init(): This method is called to initialized an applet

start(): This method is called after the initialization of the applet.

stop(): This method can be called multiple times in the life cycle of an Applet.

destroy(): This method is called only once in the life cycle of the applet when applet is destroyed.

init () method:

•       The life cycle of an applet is begin on that time when the applet is first loaded into the browser and called the init() method.

•       The init() method is called only one time in the life cycle on an applet. The init() method is basically called to read the PARAM tag in the html file. The init () method retrieve the passed parameter through the PARAM tag of html file using get Parameter() method

•       All the initialization such as initialization of variables and the objects like image, sound file are loaded in the init () method .After the initialization of the init() method user can interact with the Applet and mostly applet contains the init() method.

Start () method:

•       The start method of an applet is called after the initialization method init().

•       This method may be called multiples time when the Applet needs to be started or restarted. For Example if the user wants to return to the Applet, in this situation the start Method() of an Applet will be called by the web browser and the user will be back on the applet.

•       In the start method user can interact within the applet.

Stop () method:

•       The stop() method can be called multiple times in the life cycle of applet like the start () method. Or should be called at least one time.

•       There is only miner difference between the start() method and stop () method. Example the stop() method is called by the web browser on that time When the user leaves one applet to go another applet and the start() method is called on that time when the user wants to go back into the first program or Applet.

destroy() method:

•       The destroy() method is called only one time in the life cycle of Applet like init() method.

•       This method is called only on that time when the browser needs to Shut down.