Creating Java Applet

Posted by: Umair H. Peracha 28 April 2010 2 Comments

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Hi folks,

Today I’ll be talking about How to create Java Applet. An applet is a program written in the Java programming language that can be included in an HTML page, same as an image or Adobe Flash content.

What can HTML NOT do?
An HTML cannot do the following:

Interact with hardware
Interact with OS and tasks
Interact with hard drive

Also, all the dynamic stuff is restricted to the capability of JavaScript and VBScript. We need client code that runs on the system, can do all of the above and is secure too.An APPLET can do this job.

It is a program written in the Java and it can be included in an HTML page. It requires a Java technology-enabled browser to view a page that contains an applet.The applet’s code is transferred to the client’s system it is executed by the browser’s Java Virtual Machine (JVM). To embed the Java Applet in the web page, tag is used.To make you life easy, start building Applets using NetBeans. NetBeans is a free, easy to use IDE that allows you to quickly create and test Java Applications including an Applet.

Start NetBeans
Create New Project Select Java Application, Next
Uncheck Create Main Class, Finish
Source Package in Projects Tab
Click New, Select Java -> JApplet, Next
Specify Name (Optional), Finish
In New Window write:

import javax.swing.JApplet; import java.awt.Graphics;

/**
*
* @author Umair
*/
public class NewJApplet extends JApplet {

/**
* Initialization method that will be called after the applet is loaded
* into the browser.
*/
@Override
public void init() {
// TODO start asynchronous download of heavy resources
}

@Override
public void paint(Graphics g)
{
g.drawRect(0, 0,
getSize().width – 1, getSize().height – 1);
g.drawString(“Hello world!”, 5, 15);
}
// TODO overwrite start(), stop() and destroy() methods

}
Press Shift+F6 to run the file.
Remember, the paint function is a default function that is overridden here. It uses a Graphics object to draw text on the Applet Surface.