if I use Kolya, will I incur racism like I were Russian?
Erm... last time I checked Poles and Russians were the same race, so I have
no idea what "racism" you are talking about.
If I would incur hate for Kolya/Kolja
Why do you think you'd incure hate? That's ridiculous - you can change
your name to Adolf for all I care (and I bet other people in Poland won't
care either).