iSelfSchooling - Manuscript for how to write, compile and run a JAVA applet

A JAVA applet is not a standalone program and need JAVA runtime to run. You can run a JAVA applet using your browser. Your browser should have JAVA runtime and be enabled. You can also use the Applet Viewer included in the SDK.

Now, write a JAVA applet called IamSelfBuilder to display “I am a self builder!”

Step #1: Write and Create a JAVA applet source file

Use the notepad editor. Write, your program, IamSelfBuilder, to display the “I am a self Builder!” message as a JAVA applet program.

Then save your JAVA applet as “c:\IamSelfBuilder.java” within the double quote and exit from notepad. Be careful what you type. Notice that the JAVA compiler and interpreter are very case-sensitive.

Notice that the bold characters in the following listing are comments.

import java.applet.*;

import java.awt.*;

/***************************************************

* The IamSelfBuilder class implements an applet that

* simply displays "I am a self builder!".

***************************************************/

public class IamSelfBuilder extends Applet {

public void paint(Graphics g) {

// Display "I am a self builder!"

g.drawString("I am a self builder!", 50, 25);

}

Step #2: Compile your JAVA applet source program

Go to the MS-DOS or Command prompt and change your current directory to the directory where you saved the JAVA source program. Remember that the JAVA compiler be in your path. If it is not, then set the path (set PATH=your java path/bin).

Example: MS-DOS> c:\java folder\bin\javac IamSelfLearner.java

If there are no errors, then you have successfully compiled your JAVA applet program. Now, you have generated a JAVA applet bytecode file, IamSelfBuilder.class. Now that you have the class file (a JAVA bytecode file), you can run your program. This file can run using your browser.

Step #3: Write an HTML file

Now, you should write an HTML file to accompany your applet. Use the notepad editor. Save it as c:\IamSelfBuilder.html.

<HTML>

<HEAD>

An example of my first JAVA applet program

</CENTER></TITLE>

</HEAD>

<BODY>

This is my first JAVA applet:

</APPLET>

</BODY>

</HTML>

Step #4: Run the JAVA applet Program

You can either view your applets by using your web browser or appletviewer application.

On your web browser, simple open your browser and type your html program.

For example: c:\IamSelfBuilder.html

To use the appletviewer application, go to MS-DOS and type appletviewer IamSelfBuilder.html

For example:

MS-DOS>cd /

MS-DOS>appletviewer IamSelfBuilder.html

And your should see your applet works.

If you got the “I am a self builder” message then your program works. Congratulations!

If not, then make sure that your are in the “class” folder or you might have to change your CLASSPATH variable (set CLASSPATH=).