The paramType parameter of SetMethodInjector constructors should be of a ? extends T type instead of T, otherwise, we can't create a SetMethodInjector<Object> with a paramType different than Object.class (when using the direct type of classes in the signature instead of variables).
This will force you to create always SetMethodInjector<T> whereas T is the paramtype, thus preventing one from calling ServiceBuilder.addDependency(ServiceName, Injector<Object>).