3. Recap
In the last class ,we have studied about
• How to write a simple applet program
• We have learned the importance of each
statement in the applet program
• Let’s learn how to execute an applet
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4. Applet Execution
• Applets do not begin execution at
• main( )
• Instead, an applet begins execution when the
name of its class is passed to an applet viewer
or to a web browser
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5. Applet Execution contd..
• The steps in execution of an applet program
• Type and save the applet program with a text
editor
• Compile in the same way that you have been
compiling other Java programs
• However, running SimpleApplet involves a
different process
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6. Applet Execution contd..
• Two ways to run an applet:
1. Executing the applet within a Java-
compatible web browser
2. Using appletviewer
• An applet viewer executes your applet in a
window
• This is generally the fastest and easiest way
to test your applet
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7. Applet Execution contd..
• To execute an applet in a Web browser, you
need to write a short HTML file
• That contains the APPLET tag
• Here is the HTML file that executes
• SimpleApplet:
• <applet code="SimpleApplet" width=200
height=60>
• </applet>
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8. Applet Execution contd..
• The width and height arguments specify the
dimensions of the display area used by the
applet
• After you create this file, you can execute your
applet through web browser
• By loading this file, in the browser the
SimpleApplet program will be to be executed
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9. Applet Execution contd..
• To execute SimpleApplet with an applet viewer,
you may also execute the HTML file shown
earlier
• For example, if the preceding HTML file is called
RunApp.html
• Then the following command line will run
SimpleApplet
• C:>appletviewer RunApp.html
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10. Applet Execution contd..
• There is another approach to execute applet
using appletviewer
• The steps are
• Write the applet tag in the applet program itself inside
comments
• Write and save the applet program
• Compile as usual
• Execute applet using the following command
• appletviewer SimpleApplet.java
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11. Applet Execution contd..
SimpleApplet source file looks like this:
import java.awt.*;
import java.applet.*;
/*
<applet code="SimpleApplet" width=200 height=60>
</applet>
*/
public class SimpleApplet extends Applet {
public void paint(Graphics g) {
g.drawString("A Simple Applet", 20, 20);
}
}
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12. Summary
In this class, you have learnt
• Applets do not need a main( ) method
• Applets must be run under an applet viewer or a
Java-compatible browser
• User I/O is not accomplished with Java’s stream
I/O classes
• Instead, applets use the interface provided by
the AWT to interact with user
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