[news.eclipse.platform.rcp] NoClassDefException exception thrown when Bu

[Winters Mi <winters.mi@xxxxxxxxx>]

Hi Everyone,

   Now I am developing a RCP software using Eclipse 3.1M7. I got some 
problem when invoking Bundle.loadClass(), here is the situation.
   I declared an extension point in my core plugin, named extension 
point "command" and defined the interface that the extension class must 
implement. Then I implemented that extension point in the other plugin, 
called "helper", like
   <extension
         id="basiccommand"
         point="com.xerdoc.lifebox.commands">
      <command
            class="com.xerdoc.lifebox.helper.AboutCommand"
            command="about"
            name="About Xerdoc"/>
   </extension>
and the class implemented the interface, say IInputCommand which defined 
in core plugin and all class extend the point must implement it.

In core plugin, I look up the extension registry for the command and 
cooresponding class information. And I want to new an instance of that 
class in core plugin.
    // look up in the extension registry
    ....
    // new instance
    String symbolName = extension.getNamespace();
    Bundle bundle = Platform.getBundle(symbolName);
    Class klass = null;
    try {
	klass = bundle.loadClass(className);
        IInputCommand command = (IInputCommand)klass.newInstance();
    .....
But I caught the NoClassDefException: com/xerdoc/lifebox/IInputCommand when
    klass = bundle.loadClass(className);
I do not know why. I have added the core plugin into the dependency into 
helper plugin's manifest file (plugin.xml). Sounds like that bundle's 
class loader cannot find the core jar in his classpath.

Can you guys help me with that?
I know IPluginDescriptor has been deprecated in 3.1, so I am trying 
using OSGi.Bundle, can you guys give me some solution for such problem?

Thanks a lot!

Regards,
Winters Mi