Life cycle of an Applet.

1. A Presentation On Object Oriented Programming
Topic : LIFE CYCLE OF
APPLET
Presented By:
Richa Dasila.
160030101045
AMRAPALI INSTITUE OF TECHNOLOGY AND SCIENCES

2. CONTENTS:
Introduction.
Life Cycle.
Application.

3. Introduction:
 Java programs used in internet computing to respond the user.
 Applet=Java Byte Code + HTML page.
 They can be transported over the internet and can run using
AppletViewer / Web browser supporting java.
 Embedding Applets into web pages can be done via Local Applets or
Remote Applets .

4.  The Applet class is itself a subclass , the inheritance
may be better represented as:
java.lang.Object java.awt.Component java.awt.Container
java.awt.Paneljava.applet.Applet

5.  The Applet class uses the services of two classes namely, Applet and Graphics .
 Applet package provides life and behaviour to the applet through methods such
as init(), start() etc.
 Unlike other applications which call the main() method to execute the code .
When an applet is loaded java automatically calls a series of Applet class
method for starting,running and stopping thereby following a lifecycle.

6. Life Cycle:
Running
State
Idle
State
Dead
State.
Born
State
END.

7. BORN
STATE
init() :
This method is
used for
initialization
 Following Things can be done:
i. Objects can be created using Applet.
ii. Initial Values can be set.
iii. Colors can be set.
iv. Load fonts .
 This can be done only once in an applet’s life cycle.
BORN STATE.

8.  To provide any behaviour we must override the init() function.
 Syntax:
public void init()
{
………………..
…………..(Action)
…………………
}

9. RUNNING
STATE
start()
THE RUNING
STATE
 Applet enter this stage when :
 System calls the start() method of Applet class , this method is automatically called after
the init () .
 Applet is resumed from the idle stage after some activity by the user in different page.
• This method unlike init() can be called more than once , we may override the start()
method to create a thread to control applet.

10.  The syntax:
public void start()
{…………
……….(Action)
…………
}

11.  Applet moves to paint method to perform output operations on screen .
 This happens immediately after entering the running stage.
 The display stage is not considered as a part of applet’s life cycle .
 The default version of the display state does absolutely nothing.
 Syntax:
public void paint(Graphics g)
{……………
………(Action)
}
DISPLAY
STAGE
paint()
THE DISPLAY STAGE

12. IDLE
STATE stop()
THE IDLE STAGE:
 An Applet becomes idle when we leave the page containing the currently running
applet.
 If we use a thread to run the applet , we must use stop() method to terminate the
thread.
 We must override the stop() method.
 Syntax:
public void stop()
{………..
…..(Action)
……..
}

13. DEAD
STATE
destroy()
THE DEAD
STAGE
 Dead State = Removed from memory.
 This occurs automatically when we exit the browser
state.
 Invoking the destroy() method cleans up the
resources created by the applet.
 It can be overridden only once like the init() stage.

14.  Syntax:
public void destroy()
{
……………..
……(Action)
………….
}

15. APPLICATION:
 When we need something dynamic in the webpage :
Smart Presentation of statistical data.
 When we require flash outputs : Creative
presentation.
 Creating Remote Applets and storing them in the
internet for others to download and use.