Newbie question for ClassCastException

[Marc-Andre Houle]

I'm sure I am presently asking a really simple question that have been seen
a thousand times.  But since I don't know where to start with OSGI, I'll ask
the question here in hope that one person would help me.

We need to build a plugin management for a web application running wicket.
It is already running and I would want to include OSGI bundle
extendability.  I want bundles that are added to register as services in
order to give access to some methods.  The bundle is installed in felix
using the FileInstall activator.  I will not paste all the code since I
think the interface and implementation is irrelevant here. (Even if they are
really simple).  The problem come with the fact that I cannot cast the
service received into the interface implemented.  I get a ClassCastException
when trying to use it.

Here is the code at initialization of the web application :
//Make the felix startup here.
        Properties felixProps = new Properties();
        try {

felixProps.load(this.getClass().getResourceAsStream("/felix.properties"));
        } catch(Exception e) {
            logger.warn("Could not load felix properties", e);
        }

        List<BundleActivator> list = new ArrayList<BundleActivator>();

        FileInstall activator = new FileInstall();
        list.add(activator);

        this.panelProvider = new PanelServiceProvider();
        list.add(this.panelProvider);

        felixProps.put(FelixConstants.SYSTEMBUNDLE_ACTIVATORS_PROP, list);
        try {
            this.felix = new Felix(felixProps);
            this.felix.start();
            logger.info("Felix started.");
        } catch(Exception ex) {
            logger.error("Could not load felix", ex);
        }

Here is the code for the PanelServiceProvider class :
public class PanelServiceProvider implements BundleActivator {

    private ServiceTracker serviceTracker;
    public void start(BundleContext context) throws Exception {
        this.serviceTracker = new ServiceTracker(context,
PanelDescriptor.class.getName(), null);
        this.serviceTracker.open();
    }
    public void stop(BundleContext arg0) throws Exception {
        this.serviceTracker.close();
    }

    public List<PanelDescriptor> getAllPanelDescriptor(){
        if(this.serviceTracker != null){
            Object[] services = this.serviceTracker.getServices();
            if(services != null){
                List<PanelDescriptor> panels = new
ArrayList<PanelDescriptor>(services.length);
                for(Object service : services){
                    if(service instanceof PanelDescriptor){
                        panels.add((PanelDescriptor)service);
                    }else{
                        System.out.println("Unknown service : " +
service.getClass().getName());
                        for(Type type :
service.getClass().getGenericInterfaces()){
                            System.out.println("Implementing : " +
type.toString());
                        }
                    }
                }
                return panels;
            }
        }
        return null;
    }
}

And here is the result that I get for invoking this method when I call the
page in the web app :

Installed
c:\java\project\demo-wicket-felix\target\felix\fileinstall\panel1-0.0.1-SNAPSHOT.jar
2009-06-18 10:18:34.544::INFO:  Started selectchannelconnec...@0.0.0.0:8080
[INFO] Started Jetty Server
Unknown service : com.mycompany.panel.PanelDescriptorImpl
Implementing : interface com.mycompany.panel.PanelDescriptor


What that mean is that the serive is loaded, it can be reached, but the
classes does not come from the same classloader.  Now, I'm a little lost as
to what I'm supposed to do in this case.Does anybody have an idea on what I
could do to solve this problem?

If more details is needed (Like the manifest files or the other classes),
let met know and I'll provide them.

Thanks in advance.

Marc-Andre