IMPORTANT: Applet Problem Please Help!

nvidia · #1 (**permalink**) 01-22-2008, 02:12 AM

Hi am really new to applets. I am reading a book on creating applets and i am trying to create the HelloWorld applet. I am also using Netbeans for this. The code i have used is as follows.

Code:

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

public class HelloWorld extends Applet
{
    
    /** Creates a new instance of HelloWorld */
    public void init()
    {
        
     
    }
    
       public void paint(Graphics g) 
    {
       g.drawString("Hello Luong", 50, 25); 
    }
     
   
}

After reading this book it now tells me to compile it using the java compiler but everytime i try to compile this i ALWAYS get the message:

<no main class found>

can somebody tell me what i need to do cos i have seen this example in many tutorials and there is no main class. I have attached the project folder for viewing.

In the book it also reads that i need to create an html file with the code:

Code:


<html>
<head>
<title>
Simple Applet
</title>
</head>
<body>
   Here is the output of my applet:
<APPLET CODE = "HelloWorld.class" width = 150 height=25 </APPLET>

</body>
<html>

But before adding the html code, i need to sort out the main class issue. Can somebody give me some advice.
The location of my applet is
C:\MyNBProjects\Concurrent Programming\HelloWorld.java
Thanks

hardwired · #2 (**permalink**) 01-22-2008, 03:25 AM

Your html file applet tag has a missing bracket ( > ) in it.
I usually avoid using html/web launching of applets because of caching problems. The JRE/plug-in and my ms browsers both like to cache Applets and run them irrespective of changes to their class files.
To avoid this I develop with appletviewer, one of the tools in the sdk/jdk bin. To use it include an applet tag in a comment in your source file. Then, after compiling, run it with "appletviewer AppletName.java" at the prompt.
Here's my console output after compiling and running your applet (renamed to avoid name–clashing in your system). Trying to run it as an application generates the error: no main method found in the file.

Code:

C:\jexp>javac hw.java

C:\jexp>appletviewer HW.java

C:\jexp>java HW
Exception in thread "main" java.lang.NoSuchMethodError: main

You can add a convenience main in your applets so you can run them from the prompt with "java" if you like. Make a Frame and add the applet to the center section of the default BorderLayout. Configure and show the frame like you would for an applcation.
Here's the applet I ran in the tests shown above:

Code:

//  <applet code="HW" width="200" height="200"></applet>
//  to run: at the prompt>appletviewer HW.java
import java.applet.Applet;
import java.awt.*;

public class HW extends Applet
{
    /** Creates a new instance of HW */
    public void init()
    {
        setBackground(Color.pink);
    }

    public void paint(Graphics g) 
    {
        g.drawString("Hello Luong", 50, 25); 
    }
}