This is ridiculous. One year in prison is madness for such a thing.

One year in prison probably means that this guy is never going to complete his career (I assume he was a tutor at some university while studying there). He won't get a job afterwards. This essentially destroys his life.

Not even considering what may happen in crowded prisons.

So no, IMNSHO this is not "a just sentence".

I can't tell if you're being serious. A year in prison for changing some grades seems quite excessive. Five years of probation (that went along with the jail sentence) is plenty, I would think.