code: public JvmTypeReference getExtendedClass(JvmDeclaredType type) {
  		for(JvmTypeReference candidate: type.getSuperTypes()) {
  			JvmType candidateType = candidate.getType();
  			if (candidateType instanceof JvmGenericType && !((JvmGenericType) candidateType).isInterface())
  				return candidate;
  		}
  		return null;
  	}
docs: /* @Nullable