Looking for a novels name

I read a novel a few years ago but i forgot its name, do you guys know it?

What i still remember: The mc had a long journey to some well known school where he had 3 other roommates and they became good friends. One of them was the prince of a country, another one the son of the leader of an big trading company and the last one became a mage i think.

I remember there was a big forest in the middle of the continent which the mc had to cross at one time which took him like a few years. And then he found out a big war had started.