Mumps are a viral infection and used to be a common condition with school children before the MMR (measles, mumps, and rubella) vaccine was introduced in the UK in 1998. Mumps is a contagious condition and a person is contagious a few days before symptoms appear and are still contagious a few days after symptoms afterwards too.
This condition is spread through infected droplets of saliva breathed in through the mouth and nose, so if you were infected and you coughed then chances are someone else would get it too. So a school, college, or university is a perfect breeding ground for the virus because there are lots of potential carriers.
So if an infected person touched their nose or mouth and touched an object such as a door handle or a work surface shortly afterwards the virus could be transferred to a new host. Or if you are sharing cups or cutlery with an infected person then potentially you could get it too.
Mumps can also be passed on by people who are infected but are showing no obvious symptoms too.