You can do the same in Java and C++. This may violate a strict definition of parametricity (I've read the definition from a few different sources and am still mulling it over), but I'm not sure how this relates to parametric polymorphism.
The _behavior_ of this function is the same for all types, the _output_ is different. That is, for all types, the function body is the same. Maybe there is a more abstract definition of parametric polymorphism you are using, but as I said above, this seems pedantic.
The _behavior_ of this function is the same for all types, the _output_ is different. That is, for all types, the function body is the same. Maybe there is a more abstract definition of parametric polymorphism you are using, but as I said above, this seems pedantic.