"Barista" is not a Spanish word, and many barmen in Spain might feel their virility was being doubted if you used the word to them, since most Spanish words ending in "a" are feminine. ("Camarero" is the Spanish word for barman.) "Barista" is, however, the Italian for barman or barmaid. Clearly, both that word and "barrister" are derived from the word "bar" (or more accurately from the Latin "barra") but in one case it's a bar for dispensing drinks, and the other justice.
barista is southamerican spanish for bartender as long as i can remember, that's 40 years. i know that if you look it up an online translator it is not even there. here in the states, they use it for a coffee bar attendant instead.
True that 'barista' is not a Spanish word, and my references do not show it in current use in South America either. The Spanish for barman is 'camarero' or 'barman' (plural barmans). The Spanish for barrister is 'abogado'. Even if the answer to your question is 'no', in my experience both professions are adept at parting you from your money.