GPS/WiFi

When buying a portable device with gps and wifi, are there different levels of quality or is a gps always the same, no diffrent from any other device? I mean, is there some wifi that can read stuff like java and other that can't?

is there some wifi that can read stuff like java and other that can't?
I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.