need help urgently,about IHelperType.createHelper()

I use EMF ecore to build a custom db.it contains two classes, one's super class was simpleItem and the other one's super class is Helper . There is a reference(to the helper) in the simpleItem class(one-many).
My issue is :when i want to create a helper there is a JVM exception was throwed.I think there are caches in the eclipse may be ,but how to resolve this issue??

code snippet:
throw an Exception at createHelper():
History history = (History) getHistoryType().createHelper();


private static IHelperType getHistoryType() {
return IHelperType.IRegistry.INSTANCE.getHelperType(
DataCollectorPackage.eINSTANCE.getHistory().getName(),
DataCollectorPackage.eNS_URI);
}



Exception:
"The type org.osgi.framework.BundleContext cannot be resolved. It is indirectly referenced from required .class files

com.ibm.team.repository.common.transport.ServiceMethodInvocationError: java.lang.ExceptionInInitializerError"


additional: J9VMInternals->initialize(Class clazz)->getInitStatus(clazz) always return FAILED. This is the main reason.

Thanks very much.