Jenkins builds with Java 8 seem to be broken

[Julian Reschke]

Hi,

see <https://issues.apache.org/jira/browse/INFRA-24351> and
<https://ci-builds.apache.org/job/Jackrabbit/job/jackrabbit-oak-1.22/>.

For now, I'm switching to JDK 11 here.

Best regards, Julian