My ubuntu server reboots every two weeks or so and i can not figure why

So, i have a linux ubuntu vps where my java application runs with postgres in docker container. Java application runs in tmux session. Every two weeks or so the machine reboots and everyting is shut down.

Shortly:Is it possible that my java application use too much RAM and instead of java app throwing stackoverflow error the linux machine just crashes and reboots?

If not, which other reasons can be for my server rebooting once two weeks or so?

I tried to check the journalctl and other logs and there is not anything suspicious there. The tecnincal support of the hosting also checked the logs and found nothing suspicious.So i have two theories:

1. Hosting-side problem
2. My java application use too much RAM and instead of throwing stackoverflow error the linux machine just crashes and reboots.