Hi maddiemack,
Thanks for your reply. I'll try to be helpful and learn from the people that post here.
There is no relation between the names "Javier" and "Paquito". People who are called "Paquito" has "Francisco" as their first name. "Francisco" is the same name that "Paco" and, more familiar, "Paquito". So, your friend's name is probably "Francisco Javier". There are a lot of "Francisco Javier" in Spain. The name "Francisco" is very common in Spain followed by another name "Francisco José" "Francisco Manuel", etc...
Though my name is "Javier" and not "Francisco Javier", you can call me "Paquito" as well. When I was in England people called me whatever they wanted because the name "Javier" is very difficult to pronounce for native English speaker. I've never been called like that but it sounds funny.
Regards