Am I bluffing? I think I'm bluffing ($400NL river decision)

[the_main]

No reads on villian.

I just sat at the game, although the previous hand I called a continuation bet from diff. player, and bet the turn when he checked to me. I took down the pot.

This is the very next hand, and I am emulating the same pattern to evoke a response from worse hands.

NOTE: I know a case can be made for shoving the turn, and that might be the best play here, but I'd like to focus on the river decision, because thats where the hand becomes interesting.

Poker Stars - No Limit Hold'em Cash Game - $2/$4 Blinds - 8 Players - (LegoPoker HH Converter)

SB: $376.00
BB: $615.20
UTG: $413.00
UTG+1: $430.20
MP1: $513.00
MP2: $219.20
<font color="black">the_main (CO): $433.00</font>
BTN: $329.70

<font color="black">Preflop:</font> the_main is dealt K[img]/images/graemlins/club.gif[/img] K[img]/images/graemlins/diamond.gif[/img] (8 Players)
2 folds, <font color="red">MP1 raises to $16.00</font>, MP2 folds, the_main calls $16.00, 2 folds, BB calls $12.00

<font color="black">Flop:</font> ($50) 7[img]/images/graemlins/spade.gif[/img] 2[img]/images/graemlins/diamond.gif[/img] J[img]/images/graemlins/heart.gif[/img] (3 Players)
BB checks, <font color="red">MP1 bets $24.00</font>, the_main calls $24.00, BB folds

<font color="black">Turn:</font> ($98) 2[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">MP1 bets $28.00</font>, <font color="red">the_main raises to $72.00</font>, <font color="red">MP1 raises to $116.00</font>, the_main calls $44.00

<font color="black">River:</font> ($330) J[img]/images/graemlins/spade.gif[/img] (2 Players)
MP1 checks, <font color="red">the_main bets all-in for $277.00</font>

The only thing that can call is a J, or 22, right?
And a J can't check that river, can he?

Hands ahead that I get to fold include, 77, AA and all flushes.

Or do I have enough value to just take this to showdown (my first intstinct)?