private Class getReturnType(Method theMethod) {
        Class returnType = theMethod.getReturnType();

        if (returnType.isInterface()
                || returnType.isArray())
            return null;

        //  The primitive class type is different then the wrapper class of the
        //  primitive. We need the wrapper class.

        if (returnType.isPrimitive())
            returnType = primitives.get(returnType);

        return returnType;
    }