ClassNotFoundException in Java

Question

I have a strange and fustrating problem. I loaded all my .class files into a JAR file and placed it on my local web server. The problem is when I navigated to the page with my JAR I got a big ClassNotFoundExeption. I am 100% certian this class file is in my JAR. I also know the JAR file is in the same directory as my XHTML file

Here is the XHTML source

<html>
    <head>
    </head>
    <body bgcolor="000000">
        <center>
            <applet
                archive   = "program.jar"
                code    = "inigui4.class"
                width   = "500"
                height  = "300"
            >

            <param name="cache_option" value="no"> 
            </applet>
        </center>
    </body>
</html>

Very strange!

For some reason when I create a hello world applet I get the same problem (could it be with my LightTPD server?

Java source follows

import java.awt.*;
import java.applet.*;

public class inigui4 extends Applet {

    public void init() {
    }

    public void paint(Graphics g) {

        g.drawString("Welcome to Java!!", 50, 60 );

    }
}

Even stranger.

Now I can't load any applets on the web because I get this error. I will need to contact Oracle in the morning.

Please post the full stack trace of the exception you got. The problem is not that the JAR file itself is not found, but that a class is missing from the JAR... — ppeterka, Nov 10 '12 at 09:27
The stack trace tells you that. The long gibberish with ClassNotFoundException in it. Just copy and paste it into the question — ppeterka, Nov 10 '12 at 09:43
Sorry if I sound dumb but where can I find the gibberish? I am just clicking on the applet error window and getting ClassNotFoundExeption inigui4.class — Roland Sams, Nov 10 '12 at 09:50

score 0 · Answer 1 · edited May 23 '17 at 11:43

0

It can be caused by multiple reasons, but the most probable one is that you haven´t specified the package of the class you´re using. Look at the answer of this post.

edited May 23 '17 at 11:43

Community

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1

answered Nov 10 '12 at 09:28

Luis Andrés García

5,852
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score 0 · Answer 2 · answered Nov 10 '12 at 09:28

0

If you are using packages you have have to prefix inigui4.class by its relative path into the jar

answered Nov 10 '12 at 09:28

Aubin

14,617
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Sorry for the stupid question but how can I do stack trace on the exception... I never really learned how to run stack traces – Roland Sams Nov 10 '12 at 09:33

score 0 · Answer 3 · answered Nov 10 '12 at 09:55

I think the problem is here:

        <applet
            archive   = "program.jar"
            code    = "inigui4.class"
            width   = "500"
            height  = "300"
        >

Here, you specify inigui4.class - but in your Java code:

public class inigui_rb extends Applet {
   ...
}

This is inigui_rb. Try:

         <applet
            archive   = "program.jar"
            code    = "inigui_rb.class"
            width   = "500"
            height  = "300"
        >

The ClassNotFoundException should go away.

Also please adhere to the Java coding conventions when coding! In this case:

Class Names Begin With Capitals!
ClassNamesDoNotContainUnderscoresInsteadTheyAreCamelCased!

No, this is a new program I changed the name of the class when I built the hello world program — Roland Sams, Nov 10 '12 at 09:58
Ok, then please update the question to be coherent, as it is misleading this way. — ppeterka, Nov 10 '12 at 10:14

ClassNotFoundException in Java

3 Answers3