Ju Jitsu (also called Jiu Jitsu, Ju Jutsu, ju-jitsu etc) is steeped in Japanese history as the hand to hand fighting art of the samurai warriors.
Goshin Ju Jitsu is the modernised form of that ancient art, continuously developed and adapted to today's modern street self defense situations. Goshin Ju Jitsu is a holistic art in that it covers most self defense situations that you would be likely to encounter on today's streets and allows its practitioners a full range of responses appropriate to the given attack-defense situation.
In legal terms you 'should use the minimum amount of force to restore a safe situation', so your counter to any attack should be measured not only in line with the attack itself but also the level of danger that you are in?
Are you outnumbered, cornered, do they have weapons.. or is it simply someone showing off in front of their mates, bravado and chest puffing?
Knowing the difference and being able to think and act under pressure will help, training in Goshin Ju Jitsu will give you the right techniques when you need them most.