There is hope there if he did it in class. Keep working on it. Try "That's enough" Let him bark appropriately, but if he crosses over into inappropriate or excessive, teach him "That's enough". Make it happen by correcting, distracting, praising for what you want. If you're consistent, eventually he'll get the idea. It's all about communication between the two of you, and at age one, he's still learning. Patience, time, consistency, love and kindness will eventually yield a beautiful, understanding relationship. Good luck.