And he believes the full-back is better than ever after overcoming his Chelsea rejection.
Boss Harry Redknapp and his staff have rebuilt Johnson's shattered confidence following his Stamford Bridge experience.
Adams told the News: 'Glen's playing very well. He's doing great.
'I think you have got to keep him focused, especially defensively.
'It's about giving him pure, honest confidence. You can get praise and get carried away but the kid's got to be looked after and handled right after what he has gone through.
'I think he got knocked at Chelsea - they knocked his confidence.
'We try to put our arm round him, have a chat, look after him. I think Glen works like that.
'I would say defensively he has improved this year. If anything, last season he had complications about his positioning. There was a little bit of when you are good you want to show it, but there are times and places to do that.
'It's all about maturity and experience. The more you do it, the more you play in it, the more you are shown it. Then he's only going to improve.'