My simple applet won't run

**coffeebreak** · 11-10-2005, 02:48 PM

This problem has been solved.
The error:
java.lang.ClassFormatError: Extra bytes at the end of class file
Was caused by uploading the .class file in ascii format.

I'm new to applets so hopefully my problem will be obvious to someone:
I'm running windows XP, java 1.5.0_05

I have a file called HelloWorld.java-

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

public class HelloWorld extends Applet {
public void paint(Graphics g) {
g.drawString("Hello world!", 50, 25);
}
}
[eof]

I run this through javac to get HelloWorld.class
HelloWorld.class is uploaded to the same webpage in the same folder as index.htm-

<html>

<head>
...
</head>

<body>
...
<APPLET CODE="HelloWorld.class" WIDTH=600 HEIGHT=450>
</APPLET>
...
</body>
</html>

The page comes up, loads java, then displays the big X. It's located on geocities, but I'm told that shouldn't be a problem.

I opened the java console and it gives me a rather long list:

java.lang.ClassFormatError: Extra bytes at the end of class file HelloWorld
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at sun.applet.AppletClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.applet.AppletClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.applet.AppletClassLoader.loadCode(Unknown Source)
at sun.applet.AppletPanel.createApplet(Unknown Source)
at sun.plugin.AppletViewer.createApplet(Unknown Source)
at sun.applet.AppletPanel.runLoader(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Exception in thread "Thread-137" java.lang.NullPointerException
at sun.plugin.util.GrayBoxPainter.showLoadingError(Unknown Source)
at sun.plugin.AppletViewer.showAppletException(Unknown Source)
at sun.applet.AppletPanel.runLoader(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
java.lang.NullPointerException
at sun.plugin.util.GrayBoxPainter.showLoadingError(Unknown Source)
at sun.plugin.AppletViewer.showAppletStatus(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Exception in thread "thread applet-HelloWorld.class" java.lang.NullPointerException
at sun.plugin.util.GrayBoxPainter.showLoadingError(Unknown Source)
at sun.plugin.AppletViewer.showAppletException(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

**aniseed** · 11-10-2005, 04:24 PM

I'm not sure about this exception. Could you post the URL where your applet is hosted?

**Joe Beam** · 11-12-2005, 02:18 PM

This maybe your problem.

http://forum.java.sun.com/thread.jsp...sageID=3833950

**coffeebreak** · 11-12-2005, 04:41 PM

Thanks Joe Beam, that was the problem. Note for others: the problem was uploading the .class file in ascii format.
Geocities only allows ascii uploading, no ftp, so I guess I'd better find a better site.