interfaceClasses.add(Serializable.class);
    Object dummy =
        Proxy.newProxyInstance(
            interfaceClasses.iterator().next().getClassLoader(),
            interfaceClasses.toArray(new Class<?>[interfaceClasses.size()]),
            new DummyHandler(interfaceType));
    @SuppressWarnings("unchecked") // interfaceType is T
    T result = (T) dummy;
    return result;
  }

    interfaceClasses.add(Serializable.class);
    Object dummy =
        Proxy.newProxyInstance(
            interfaceClasses.iterator().next().getClassLoader(),
            interfaceClasses.toArray(new Class<?>[interfaceClasses.size()]),
            new DummyHandler(interfaceType));
    @SuppressWarnings("unchecked") // interfaceType is T
    T result = (T) dummy;
    return result;
  }