Villain 34/5/1 over 100 hands, no other reads

Ultimate Bet No-Limit Hold'em, $.25 BB (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Button ($13.05)
SB ($9.10)
BB ($24.25)
UTG ($27.75)
UTG+1 ($7.15)
MP1 ($31.30)
Hero ($36.50)
CO ($26.10)

Preflop: Hero is MP2 with A, J.
UTG raises to $0.5, 2 folds, Hero calls $0.50, 3 folds, BB calls $0.25.

Flop: ($1.60) J, A, 8 (3 players)
BB checks, UTG bets $5, Hero raises to $12, BB folds, UTG calls $7.

Turn: ($25.60) K (2 players)
UTG bets $15.25 (All-In), Hero???.