Right set up does require some farming elsewhere.
Bravely default 2 jp farming. I farmed at crescent island in chapter 3. 1 turn victor new to bravely second taking out all enemies within one turn opens the option of engaging in another battle and your exp and jp will gain a multiplier. I maxed out all the jobs that you have at chapter 3 there. Because of that farming pg is only viable here in the early game before you acquire the growth egg.
For bravely default on the 3ds a gamefaqs message board topic titled good place to farm pg jp in chapter 5. Just auto battle with a few tweaks to account for different monsters at night and day. For bravely default on the 3ds a gamefaqs message board topic titled excellent way to exp and jp farm in chapter 2. With a growth egg and jp up you will always require exactly a 2 battle chain to reach 999 jp.
You can get anywhere from 90 306 jp relatively easily with right set up. The more times you do it. Any item that raises agi and any item that raises first.