2. Applet is a special type of program that is embedded in the webpage to generate
the dynamic content. It runs inside the browser and works at client side.
Advantage of Applet
There are many advantages of applet. They are as follows:
• It works at client side so less response time.
• Secured
• It can be executed by browsers running under many plateforms, including
Linux, Windows, Mac Os etc.
Drawback of Applet
• Plugin is required at client browser to execute applet.
4. Lifecycle of Java Applet
1. Applet is initialized.
2. Applet is started.
3. Applet is painted.
4. Applet is stopped.
5. Applet is destroyed.
5. Lifecycle methods for Applet:
The java.applet.Applet class 4 life cycle methods
and java.awt.Component class provides 1 life
cycle methods for an applet.
java.applet.Applet class
For creating any applet java.applet.Applet class
must be inherited. It provides 4 life cycle
methods of applet.
6. 4 life cycle methods of applet
1. public void init(): is used to initialized the Applet. It is
invoked only once.
2. public void start(): is invoked after the init() method or
browser is maximized. It is used to start the Applet.
3. public void stop(): is used to stop the Applet. It is
invoked when Applet is stop or browser is minimized.
4. public void destroy(): is used to destroy the Applet. It is
invoked only once.
7. How to run an Applet?
There are two ways to run an applet
1. By html file.
2. By appletViewer tool (for testing purpose).
9. //First.java
import java.applet.Applet;
import java.awt.Graphics;
public class First extends Applet{
public void paint(Graphics g){
g.drawString("welcome to applet",150,150);
}
}
/*
<applet code="First.class" width="300" height="300
">
</applet>
*/
c:>javac First.java
c:>appletviewer First.java
10. Displaying Graphics in Applet
1. public abstract void drawString(String str, int x, int y): is used to
draw the specified string.
2. public void drawRect(int x, int y, int width, int height): draws a
rectangle with the specified width and height.
3. public abstract void fillRect(int x, int y, int width, int height): is used
to fill rectangle with the default color and specified width and height.
4. public abstract void drawOval(int x, int y, int width, int height): is
used to draw oval with the specified width and height.
5. public abstract void fillOval(int x, int y, int width, int height): is used
to fill oval with the default color and specified width and height.
11. 1. public abstract void drawLine(int x1, int y1, int x2, int y2): is used
to draw line between the points(x1, y1) and (x2, y2).
2. public abstract boolean drawImage(Image img, int x, int y,
ImageObserver observer): is used draw the specified image.
3. public abstract void drawArc(int x, int y, int width, int height, int
startAngle, int arcAngle): is used draw a circular or elliptical arc.
4. public abstract void fillArc(int x, int y, int width, int height, int
startAngle, int arcAngle): is used to fill a circular or elliptical arc.
5. public abstract void setColor(Color c): is used to set the graphics
current color to the specified color.
6. public abstract void setFont(Font font): is used to set the graphics
current font to the specified font.
12. import java.applet.Applet;
import java.awt.*;
public class GraphicsDemo extends Applet{
public void paint(Graphics g){
g.setColor(Color.red);
g.drawString("Welcome",50, 50);
g.drawLine(20,30,20,300);
g.drawRect(70,100,30,30);
g.fillRect(170,100,30,30);
g.drawOval(70,200,30,30);
g.setColor(Color.pink);
g.fillOval(170,200,30,30);
g.drawArc(90,150,30,30,30,270);
g.fillArc(270,150,30,30,0,180);
}
}
14. Displaying Image in Applet
Applet is mostly used in games and animation. For
this purpose image is required to be displayed. The
java.awt.Graphics class provide a method
drawImage() to display the image.
1. public URL getDocumentBase(): is used to return
the URL of the document in which applet is
embedded.
2. public URL getCodeBase(): is used to return the
base URL.
15. import java.awt.*;
import java.applet.*;
public class DisplayImage extends Applet {
Image picture;
public void init() {
picture = getImage(getDocumentBase(),"sonoo.jpg");
}
public void paint(Graphics g) {
g.drawImage(picture, 30,30, this);
}
}
