Justin was the subject to a bid from Nottingham Forest in the summer, before the 19-year-old penned a new contract until 2020 with the potential for a further year.
The England Under-20 right-back has been in impressive form since his return to the starting 11 last month, but Jones said the club haven't received a concrete offer from any side.
He said: "We've not had anything official, but there's a lot of people talking about James Justin. We had 36 scouts here the other day, which is a phenomenal amount of scouts for any football game, let alone our Checkatrade game.
"If I was to put every single one of our players on the transfer list, I would imagine we would earn a hell of a lot of money, but we're not in the business of doing that. We've taken a long time and a lot of hard work to assemble this fine squad we have. We like testing it, what we don't like doing is losing them."
He added: "We've got a lot of good footballers here, now whether we get bids is one thing, whether we accept them is a million miles from whether we get them or not. Because we want to achieve something here, we regularly turn down approaches for staff and players at this football club, so we're used to that.
"We have a focus and a goal of what we want to achieve and that means keeping hold of your best players."
The gaffer suggested there might be space for another centre-back in the squad given Scott Cuthbert is still out injured, but there's nothing in the pipeline at the moment.
"That's the only issue where we're remotely light, centre-half," Jones continued. "But we have good ones here, in terms of Alan Sheehan, Johnny Mullins, Glen Rea and Akin Famewo.
"So we're well covered in that area, but that's the only area where we're exposed slightly with obviously Sheehan being suspended and Glen has done excellently well in the defensive midfield role.
"So if an opportunity comes we can strengthen the squad then we'll always take that, whether it's a goalkeeper, forward, centre-half or wherever, but at the minute, no news.
"I speak regularly anyway with Gary Sweet. I've got a fantastic relationship with Gary. We'll need to speak over the window, because the window's open and it means targets that we have in June, for example, could become available now.
"I don't envisage there being masses of business. If there is, then it means we'll come out of this window a lot stronger than we've gone into it."
Akin Famewo shone on Tuesday evening against Peterborough United in the Checkatrade Trophy as the Hatters went out on penalties, but Jones doesn't want to put him into the side that starts against Chesterfield for the sake of it.
Jones continued: "We know what we've got in Akin, it's just no point lobbing people in and asking them to sink or swim. We think we've handled Akin really, really well.
"There'll come a time where we won't be able to hold him back any longer, but he'll have had the tools to be able to affect a League Two game and that's what we feel. He's an athlete, he's a real front foot defender which we like here, so I don't think it lessens anything, that will not affect what we do in the window.
"He's in contention, he's always in contention because we know what we've got in Akin. It was a real good test for him the other night against the front three of a real free-scoring Peterborough side, and he did fantastically well.
"It's not just about throwing him in, it's about putting him in at the right times. Up until now they haven't quite been right as we've had a very good one in Alan Sheehan, who's slightly ahead of him, and a more experienced one in Mullins. But he's earned an opportunity and we know he's ready for when he does get one."
