Test against Java 21 in CI.

Author: jxblum

Jenkinsfile

@@ -40,10 +40,10 @@ pipeline {
 						}
 					}
 				}
-				stage('Publish JDK 20 + Redis 6.2 Docker Image') {
+				stage('Publish JDK 21 + Redis 6.2 Docker Image') {
 					when {
 						anyOf {
-							changeset "ci/openjdk20-redis-6.2/Dockerfile"
+							changeset "ci/openjdk21-redis-6.2/Dockerfile"
 							changeset "Makefile"
 							changeset "ci/pipeline.properties"
 						}

ci/openjdk20-redis-6.2/Dockerfile renamed to ci/openjdk21-redis-6.2/Dockerfile

@@ -1,10 +1,10 @@
 # Java versions
 java.main.tag=17.0.6_10-jdk-focal
-java.next.tag=20-jdk-jammy
+java.next.tag=21-jdk-bullseye
 
 # Docker container images - standard
 docker.java.main.image=harbor-repo.vmware.com/dockerhub-proxy-cache/library/eclipse-temurin:${java.main.tag}
-docker.java.next.image=harbor-repo.vmware.com/dockerhub-proxy-cache/library/eclipse-temurin:${java.next.tag}
+docker.java.next.image=harbor-repo.vmware.com/dockerhub-proxy-cache/library/openjdk:${java.next.tag}
 
 # Supported versions of MongoDB
 docker.mongodb.4.4.version=4.4.18