Probably it would get picked up by someone else (e.g. the Linux Foundation)? It's GPLv2-licensed, so it's not like the code is going to be risky for someone to fork
I don't think Oracle will die, but even entertaining the hypothetical I suspect that some other organization (e.g. Apache) would pick up and maintain a fork.
IBM, Red Hat, Microsoft, SAP, Amazon and others all work on the JDK. They would have to step it up to cover the loss of Oracle's contributions, but I am sure they could manage.
Regardless, your timeframe on Oracle's death seems way too soon.