There are lots of vendors who will continue to support Java 8 given it's LTS until 2024(?). Discussion has started around officially supporting Java 11 for 4.x but that won't happen until after 4.0 GA.
We encourage everyone in the community to actively test C* 4.0 with Java 11 so it becomes a known quantity as more and more organisations test it at scale. But as far as C* 3.11 is concerned, it will only be supported on Java 8 (but never say never 😉). I'm not close to the action but FWIW, I know that there's a lot of excitement around ZGC and Java 17 being LTS (but don't quote me). Cheers!
