Wait, you only have one set of finals per year? Wouldn't that mean you take the same classes all year? That sounds awful.
Things may have changed a bit now; but when I was at uni, at Oxford, finals were the single set of exams at the end of the three years. We were tested on everything we had learnt at that point. Actually, there were also public exams ("moderations") at the end of the first year, but in most subjects these didn't count in the final degree - though they might get mentioned (a "double first" means a first in both mods and greats, where "greats" is the finals exam in classics). In sciences, practical work through the course was also assessed and fed into finals as a "paper" in its own right.
Colleges also hold exams a couple of times a year, known as "collections", which are used by tutors to keep tabs on your progress, and for disciplinary purposes
in extremis. But at Oxford, colleges are separate bodies from the university.