I have tried setting JNAME=zulu11-ca-amd64 under Cluster > Advanced options > Spark > Environment variables but it doesn't seem to work. I still get errors indicating Java 8 is the JRE and in the Spark UI under "Environment" I still see:

Java Home: /usr/lib/jvm/zulu8-ca-amd64/jre

Java Version: 1.8.0_302 (Azul Systems, Inc.)

I am using cluster version "11.2.x-scala2.12".