I've had a black bear (both were brown in colour though) act very aggressively to me to and used the 2 rock method... Not for a second did I think my life wasn't in extreme danger as I was about to be pinned between 2 bears on a trail with no escape route (blackberrys) ... Had to run at the bear leaving about 10' feet between us, then running past the bear while hammering the 2 rocks to keep the bear back as I had 2 dogs off leash and had it trapped us between the other bear it would have been really bad!!! A growling bear in very close proximity is quite... Thrilling, lol, and the other bear seemed pretty cool at less then 10' but that can change very quickly as he wasn't aware of the other growling one who seemed pretty pissed off at us, lol. It was very much a decision I made thinking if this doesn't work were dead, lol. It was the best decision but a tough one...
Ever throw a rock at a human... Only pisses them off, lol. Same with a bear...
Know of a guy who unloaded a 357 on a grizzly bear... He still died, lol. If it comes to the point it's attacking... You're screwed, lol. Don't piss it off, lol. Play dead at that point, or better yet just keep it at a bay... don't make it worse! Or provocative it into a fight... You won't win...
That said most black bears are pretty chill or scared of you... Just stay calm and you'll probably be fine