My simple applet won't run


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  1. #1
    Join Date
    Nov 2005
    Posts
    4

    My simple applet won't run

    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)
    Last edited by coffeebreak; 11-12-2005 at 04:45 PM.

  2. #2
    Join Date
    Oct 2005
    Location
    New Jersey
    Posts
    255
    I'm not sure about this exception. Could you post the URL where your applet is hosted?
    Happiness is good health and a bad memory.

  3. #3
    Join Date
    Oct 2005
    Posts
    107

  4. #4
    Join Date
    Nov 2005
    Posts
    4
    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.

  5. #5
    Join Date
    Sep 2005
    Posts
    10
    Hi..did u find any site that supports ftp upload ..do let me know..thanx

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