A not uncommon name which was often altered; the ending -vic is usually pronounced -vitch. Jeri also is correct, -witz is pronounced the same (pretty much) when altered into English, and Jus- seems to be Polish rather than more southerly.
Also easy to have a Ja- changed to Ju-.
And a Ja- to a Jas-
and a -tz to a -vich

Basque? Dunno what the original could have been. Josep(e or a) is Joseph, but I know nothing of that language (nothing like Spanish).