j3d-example Resources.getResource not found...

Sorry, I’m actually building and testing
j3d-examples in Eclipse 3.5.1 IDE, under WindowsXP.

Resources is actually defined as the attached file. In fact, this Resource.java file is as simple as

package org.jdesktop.j3d.examples;

import java.net.URL;

/**
 * 
 */
public class Resources {
    
    /**
     * Do not construct an instance of this class.
     */
    private Resources() {
        
    }

    /**
     * Return the URL of the filename under the resources directory
     */
    public static URL getResource(String filename) {    
         URL url = Resources.class.getResource(filename); 
         return url;
    }
    
    
}

I tacked into the source, it seems the function

public java.net.URL getResource(String name)

in class

java.lang.Class

can’t find the resource files, which makes url in

URL url = Resources.class.getResource(filename); 

always be null.

Can you please help?

Cheers
JIA Pei