Hello, i have a hunter and today bought heirlooms for a feral druid (head, shoulder, chest, pants and cloak) and need 3500 more for the mace and someone say fast way is heroics, other say bg (turn honor) and other say scenarios :S.
I've found that running scenarios gains JP fairly quickly, with one twist: Queue for specifics scenarios. You get 85JP at the end of each specific Scenario, 25 more than you'd get from the cache if you did randoms. Now, this works best for straight DPS such as you and my warlock, as we have halfhour wait times for heroics half the time... Of course, you could also queue for heroics while you're doing the scenarios, and just grind out the scenarios while waiting for your heroic queue to pop, and get the best of both worlds.
kill the 5.2 rares in krasarang, which gives the honor marks, use guild battle standard thingie while clicking the honor tokens (they give 313,5 with standard) and turn the honor into JP, made around 3k in a couple of hours, of which I only spend a few min/hour killing them
alot of JP for very little work
If you have a tank, run heroics. You can chain pull and get through each heroic in under 10 mins, 120 JP per boss, 3-4 bosses per instance = 360-480 per 10 mins = 2,160 - 2,880 per hour. In under two hours, you're JP capped.