Java Applet

What is a Java applet?

A Java applet is a small application which is written in Java and delivered to users in the form of bytecode. The user launches the Java applet from a web page, and the applet is then executed within a Java Virtual Machine (JVM) in a process separate from the web browser itself.

What is the difference between application and applet?

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. An application is a standalone Java program that runs as a true application, outside of a browser. Both require a JVM (Java Virtual Machine).

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 platforms, including Linux, Windows, Mac OS etc.
Drawback of Applet
  • Plugin is required at client browser to execute applet.

Hierarchy of Applet

 



As displayed in the above diagram, Applet class extends Panel. Panel class extends Container which is the subclass of Component.

Lifecycle of Java Applet

  1. Applet is initialized.
  2. Applet is started.
  3. Applet is painted.
  4. Applet is stopped.
  5. Applet is destroyed.
How to run an Applet?

There are two ways to run an applet

1.      By html file.
2.      By AppletViewer tool (for testing purpose).


Examples of Applet Program


AppletExample.java

/*
        Basic Java Applet Example
        This Java example shows how to create a basic applet using Java Applet class.
*/

import java.applet.Applet;
import java.awt.Graphics;

/*
        <applet code = "AppletExample" width = 200 height = 200>
        </applet>
*/
public class AppletExample extends Applet{
      
        public void paint(Graphics g){
                //write text using drawString method of Graphics class
                g.drawString("Shree Matrumandir College, Rajkot",20,100);
        }
}



AppletImage.java

import java.awt.*; 
import java.applet.*; 
 
/*
<applet code="AppletImage" width=300 height=300>
</applet>
*/
  public class AppletImage extends Applet
{   
  Image pic; 
 
  public void init()
  { 
            pic = getImage(getDocumentBase(),"Gujarat.jpg");
  } 
   
  public void paint(Graphics g)
  { 
    g.drawImage(pic, 30,30, this); 
  }     
}





AppletColors.java

/*
        Print INDIA in an Applet in different Colors Example       
*/

import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Color;

/*
        <applet code = "AppletColors" width = 300 height = 300>
        </applet>
*/

public class AppletColors extends Applet{
      
        public void paint(Graphics g){
              
                Color c[] = { Color.blue, Color.cyan, Color.darkGray,
                                      Color.gray, Color.green, Color.lightGray,
                                      Color.magenta, Color.orange, Color.pink,
                                     Color.red, Color.white, Color.yellow };
               
                                                //this will create light blue color
                Color customColor = new Color(10,10,255);              
                //set background color of an applet
                this.setBackground(customColor);
                                               
                for(int  i = 0; i<c.length; i++){
                        g.setColor(c[i]);
                        g.drawString(" I N D I A ", 20, 20 + (i*25));
                }
        }
}




AppletAnimation.java

import java.awt.*;
import java.applet.*;

public class AppletAnimation extends Applet
  {
    Image pic;
    public void init()
      {
        pic=getImage(getDocumentBase(),"smiley.jpg");
      }
    public void paint(Graphics grp)
      {
        for(int i=50;i<100;i++)
          {
            grp.drawImage(pic, i,50,this);
            try
              {
                Thread.sleep(300);
              }
            catch(Exception e){}
          }
      }
  }
/*
<applet code="AppletAnimation.class" width="400" height="400">
</applet
*/


AppletGraphics1.java

import java.awt.*;
import java.applet.*;
/*
<applet code="AppletGraphics1" width=300 height=300>
</applet>
*/
public class AppletGraphics1 extends Applet
{
            public void paint(Graphics g)
            {
                        for(int i=0;i<=250;i++)
                        {
                                    Color c1=new Color(35-i,55-i,110-i);
                                    g.setColor(c1);
                                    g.drawRect(250+i,250+i,100+i,100+i);
                                    g.drawOval(100+i,100+i,50+i,50+i);
                                    g.drawLine(50+i,20+i,10+i,10+i);
                        }
            }
}



AppletKey.java

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
/*
<applet code="AppletKey" width=300 height=400>
</applet>
*/
public class AppletKey extends Applet
implements KeyListener
{
            int X=20,Y=30;
            String msg="Key Events--->";
            public void init()
            {
                        addKeyListener(this);
                        requestFocus();
                        setBackground(Color.blue);
                        setForeground(Color.red);
            }
            public void keyPressed(KeyEvent k)
            {
                        showStatus("KeyDown");
                        int key=k.getKeyCode();
                        switch(key)
                        {
                                    case KeyEvent.VK_UP:
                                                showStatus("Key Up");
                                                break;
                                    case KeyEvent.VK_DOWN:
                                                showStatus("Key Down");
                                                break;
                                    case KeyEvent.VK_LEFT:
                                                showStatus("Key Left");
                                                break;
                                    case KeyEvent.VK_RIGHT:
                                                showStatus("Key Right");
                                                break;
                        }
                        repaint();
            }
            public void keyReleased(KeyEvent k)
            {
                        showStatus("Key Up");
            }
            public void keyTyped(KeyEvent k)
            {
                        msg+=k.getKeyChar();
                        repaint();
            }
            public void paint(Graphics g)
            {
                        g.drawString(msg,X,Y);
            }
}



Comments

Post a Comment

Popular posts from this blog

પટેલ સમાજનો ઈતિહાસ જાણો : કોણ અને ક્યાંથી આવ્યા હતા પાટીદારો

PATIDAR The  Patidar  are a  caste  found in the state of  Gujarat , India. They were formally recognized as a separate identity in the 1931 census of India, having previously been classified as  Kanbi . They are among the most studied of Indian castes and the process leading to their recognition is a paradigmatic example of the  invention of tradition  by social groups in India. પટેલ અથવા પાટીદાર અથવા કણબી એ ભારત દેશનાં પશ્ચિમ ભાગમાં આવેલા ગુજરાત રાજ્યની એક મુખ્ય જ્ઞાતિ છે. પટેલોમાં લેઉવા પટેલ અને કડવા પટેલ એમ બે પેટા જ્ઞાતિ છે. ઇતિહાસ તેઓ કુર્મઋષિનાં વંશજો હોવાનુ મનાય છે તેથી તેઓ શરૂઆતમાં કુર્મી તરીકે જ ઓળખાતા હતાં. ઇતિહાસકારોનાં મત અનુસાર પટેલો મધ્ય એશિયા માં આસુ નદી પાસે પામીર નામનાં ઉચ્ચ પ્રદેશમાં વસતા હતાં. ત્યાંથી એક સમુહે અફઘાનિસ્તાન માં થઈને હિન્દુકુશ પર્વતમાળા ઓળંગી ખૈબરઘાટનાં માર્ગે પંજાબ માં દાખલ થઈને વસવાટ કર્યો હતો તેમ કહેવાય છે. ભારત દેશમાં પંજાબના સપ્તસિંઘુ પ્રદેશ ‘લેયા’ પ્રદેશમાંથી આવેલા કૂર્મિ ક્ષત્રિયો લેઉઆ કહેવાય...
Read more

Python HTML Generator using Yattag Part 1

Python HTML Generator Download and install yattag pip install yattag You can download the archive here: https://pypi.python.org/pypi/yattag                python setup.py install      or:         python3 setup.py install Yattag is a Python library for generating HTML or XML in a pythonic way. With Yattag, ·         you don't have to worry about closing HTML tags ·         your HTML templates are Python code. Not a weird template language. Just Python. ·         you can easily render HTML forms, with defaults values and error messages. It's actually easier and more readable to generate dynamic HTML with Yattag than to write static HTML. 1. Tags and text from yattag import Doc ...
Read more

Java Event Delegation Model, Listener and Adapter Classes

Image
Java Event Delegation Model The Delegation Event model is one of the many techniques used to handle events in GUI (Graphical User Interface) programming languages. GUI represents a system where an user visually/graphically interacts with the system. Other interactive systems are text based or called CUI (Character User Interface). CUI interacts with the system by typing out commands in the console. GUI programming is inherently event driven; that means, whenever an user initiates an activity such as a mouse move that changes the co-ordinates of the mouse pointer in the screen, or clicks a button, scrolls a page, and so forth, each is deemed as an event that the GUI event handler maps the activity to a piece of code that explains what response the application should provide to the user. Any program that uses GUI (graphical user interface) such as Java application written for windows, is event driven. Event describes the change in state of any object.  For Example:  Pre...
Read more