400 nl confusing river raise

[NaDaChip4U]

game was on 2-4 nl (6max) on stars and villian(X) has been playing tight. i havent seen him get out of line once and seems to be winning a lot today. ive lost few big pots before and was not playing good at all. he probably views me as lag and semi bad.

hero($480) in first position raise to $14 with AJo and X ($1220) calls on cutoff and so as button.
Flop: A 4 2 r
hero bets $40 and X calls, button folds
Turn: 7 with no flush draw possible
hero checks and X checks behind
River: J
hero bets $120 and X raises all in, about $310 more tocall

i was really confused with his river raise because he played like pair of ace with ok kicker until the river, but when he puts all his money on river he had very good hands all the time.