It's clear that John, and the other Gospel writers assumed Judas, while remorseful, was NOT repentant--and therefore went to Hell. The fact that in that certain circumstance he took "justice" into his own hands too, killing himself--indicates as clearly as the bible does....that Judas did not accept God's forgiveness and therefore went to hell (not that every suicide indicates this...but this one sure seems to).
Obviously God knows all, and is the Judge--and that is something all human discernment is grounded upon--our own judgment is never "final." Given that caveat though, I have no trouble with agreeing with the Gospels, and the early Church writers too, that Judas most certainly did not go to Heaven, but died for this despicable deed and all his sins.
I have about the same level of confidence about Hitler, Stalin, Mao, and Pol Pot too--as none of them evidenced any repentance for their evil deeds. To not be (humanly) sure on such things to me shows a serious lack of certainty about ones faith...and falls dangerously close to wimpy, post-modernist-uncertain-relativism.
I’m not sayiang I disagree and I have my own opinions, but we can never be sure. Who knows what goes on between a human’s heart and God’s in the final moments.