Thread: Funny NullPointerException

Hi,

Sorry for my bad english - I'm a Swede.

I've written a pretty large Java Applet that runs fine with the appletviewer and in any browser if I run it from disc. But when I've uploaded it to my webpage it produces a NullPointerException. I've scaled down the program to a silly minimum in order to find out what's going wrong. Now, the code looks like this:

import java.applet.*;
import java.awt.Graphics;
 
public class JavaTest extends java.applet.Applet {
 
    public class Dummy {
        public Dummy() {}
    }
    public Dummy ReturnNull() {
        return null;
    }
    public void init() {}
    public void paint(Graphics g) {}
    public void start() {}
    public void stop() {}
    public void run() {}
}

Don't mind the run, the original version of the applet uses a thread. However the program above generates a NullPointerException if I run it on my web page. But if I remove the function named ReturnDummy, it runs fine.

Does anyone have an idea of why I can't have a function that returns an instance of an inner class?

Best regards
Marcus

Just so that you don't think I'm a complete muppet ...

The actual applet (not the dummy-version I just posted to show what goes wrong) is produced by my own little programming language (see link: NaaLaa). I'm trying to make it generate java applets instead of windows programs, so that not-so-good-programmers should be able to make games for the web. And it works very well as long as I run the applets from disc via the appletviewer, internet explorer or firefox. But when I put an applet on the web, the mere existance of a function that returns an instance of an inner class causes the nullpointerexception to be generated.

/Marcus

Well, I found some more:

network: Cachepost not found [webbadress: http://www.naalaa.com/javatest$Dummy.class, version: null]
network: Connecting http://www.naalaa.com/javatest$Dummy.class with proxy DIRECT
network: Connecting NaaLaa with proxy DIRECT
basic: exception: null.
java.lang.NullPointerException
at sun.plugin2.applet.Plugin2Manager.findAppletJDKLev el(Unknown Source)
at sun.plugin2.applet.Plugin2Manager.createApplet(Unk nown Source)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionR unnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

I am a complete beginner when it comes to java, so I don't know exactly what this is about or what I'm talking about. But if I interpret this right, he's looking for a .class-file for the inner class. I assumed he baked them into one file - javatest.class. I guess that explains it all. Sorry for not thinking.