Responses

I wouldn't go that far as saying he changed, seeing how things repeated.
Obviously in his time in juvi John learned one thing, he had to supress himself to fit the order.
He didn't read the report on the facts nor he was really concious on why what he did was wrong, he just understood that shit went out of control when he let loose, so he mustn't let loose, he thought
Well, he thought wrong. Didn't learn anything at all.
Basically John has always been a piece of shit