[Dave G.]

I'm not capping preflop with JJ without some kind of read on button as a loose preflop raiser. What legitimate 3-betting hands are you infront of here? Really only AK and AQ (and some people wouldn't 3-bet AQ). Everything else has you crushed, and 3 overcards can come to beat you on the flop as well. Just call the 3-bet and see how the flop develops.

I'd fold when it comes back two to me on the flop, because there's the chance of getting it capped behind you. Folding for one bet to the cap is pretty bad though, the pot is massive. If a J came on the turn, you would probably be on tilt for the rest of the night.