Kryonet hosting? Where and how?

It’s kinda embarrassing how I’m littering this forum but ah well, it’s not like I wasn’t trying this on my own since this morning.

I have a game that consists of a java “Server” using kryonet. With the server on my laptop and router forwarding, everything works fine (client is an android phone, communicates with the server via mobile internet, not wlan/lan).

How do I get this thing online? I’ve looked at and tried a whole bunch of approaches, the closest I came was on heroku but there I’m seemingly unable to make up the correct Procfile (I got as far as deploying my application on there, but without the correct Procfile command it won’t even try to start).

I feel I’m conceptually missing something, obviously I’m not the brightest guy around but if it’s so easy to run locally, can it really be this hard to just upload my project as is (git is fine) and then it’ll simply run as if the host were my laptop? I basically only need a computer that has java installed, right?

Hosting doesn’t have to be free but I definitely only need whatever the lowest tier is anywhere as I’m only testing stuff.