I was wondering if it was possible to do judo and bodybuilding together. Is it possible to compete in judo and an amateur level while doing bodybuilding?
Yes, you can do amateur judo and bodybuilding together. The only major potential conflict that comes to mind is nutrition, and if you are not planning on cutting weight for amateur judo competitions (which I would recommend against), this is moot.
To succeed in judo competition, you need both skill and strength. Make sure that you do not rely on strength to make up for deficiencies in skill.