SpringBoot Upgrade to a Cassandra version that works with Java 9

See CASSANDRA-9608. Our sample is disabled on Java 9 at the moment.

See also https://github.com/jsevellec/cassandra-unit/issues/249

Comment From: wilkinsona

https://issues.apache.org/jira/browse/CASSANDRA-9608 has been fixed in Cassandra 4.0. We may want to consider switching from Cassandra Unit to Testcontainers in the smoke test.

Comment From: dreis2211

Given that the smoke test was removed in ca1710ee56d327e46a76f028f7bbc12dc974ee5e and we're on Cassandra 4+ I guess this can be closed.

Comment From: snicoll

Indeed, the upgrade to Cassandra v4 was done as part of the upgrade to Spring Data Neumann, see #19588

Comment From: skyhirider

https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-with-Java-9-and-above notes java 9 is not fully supported, is the documentation outdated?

Comment From: snicoll

@skyhirider good catch, I've updated the wiki page as well. Thanks for reporting it!