Good spot to go for a river checkraise to extract max value?

[SilentNoise]

Poker Stars - No Limit Hold'em Cash Game - $1/$2 Blinds - 5 Players - (LegoPoker Hand History Converter)

SuperHero (SB): $400.30
BB: $192.00
UTG: $219.05
CO: $259.10
BTN: $90.25

Reads: <font color="blue">readless</font>

Preflop: SuperHero is dealt A[img]/images/graemlins/heart.gif[/img] J[img]/images/graemlins/diamond.gif[/img] (5 Players)
<font color="red">UTG raises to $4.00</font>, 2 folds, SuperHero calls $3.00, BB calls $2.00

Flop: ($12) J[img]/images/graemlins/club.gif[/img] 6[img]/images/graemlins/diamond.gif[/img] A[img]/images/graemlins/diamond.gif[/img] (3 Players)
<font color="red">SuperHero bets $12.00</font>, BB folds, UTG calls $12.00

Turn: ($36) A[img]/images/graemlins/club.gif[/img] (2 Players)
<font color="red">SuperHero bets $34.00</font>, UTG calls $34.00

River: ($104) 8[img]/images/graemlins/heart.gif[/img] (2 Players)
<font color="red">SuperHero bets all-in for $350.30</font>


That is how i actually played the hand but i was thinking:

1) is a unknown readless who has just come to the table really going to call a bet/bet/shove line with just a J here?

2) If i check, he may decide to make a thin value bet with KJ or something

3) if he has Ax,im sure even an unknown is value betting trips on the river, and probably wont fold to a shove

4) it gives him a chance to bet his busted flush/gutshot draws


thoughts?