code: public static Instance getInstance(Service s, Class<?> clazz)
              throws NoSuchAlgorithmException {
          Object instance = s.newInstance(null);
          checkSuperClass(s, instance.getClass(), clazz);
          return new Instance(s.getProvider(), instance);
      }
docs: /*
  The two getInstance() methods below take a service. They are
  intended for classes that cannot use the standard methods, e.g.
  because they implement delayed provider selection like the
  Signature class.