Update to Java 21 for releases

We've been using it for tests for a while already (#657). Into the future /o/

Signed-off-by: Matthias Rampke <matthias@prometheus.io>

Author: matthiasr

.github/workflows/maven.yml

@@ -19,10 +19,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-    - name: Set up JDK 17
+    - name: Set up JDK 21
       uses: actions/setup-java@v4
       with:
-        java-version: '17'
+        java-version: '21'
         distribution: 'temurin'
         cache: maven
     - name: test
@@ -32,4 +32,4 @@ jobs:
 
     # Upload the full dependency graph to GitHub to improve the quality of Dependabot alerts this repository can receive
     - name: Update dependency graph
-      uses: advanced-security/maven-dependency-submission-action@v4.1.1 # Downgraded from 4.0.1 due to https://github.com/advanced-security/maven-dependency-submission-action/issues/65
+      uses: advanced-security/maven-dependency-submission-action@v4.1.1

Dockerfile

@@ -1,4 +1,4 @@
-FROM eclipse-temurin:17-jdk-focal as builder
+FROM eclipse-temurin:21-jdk-noble as builder
 
 SHELL ["/bin/bash", "-xe", "-o", "pipefail", "-c"]
 
@@ -14,14 +14,10 @@ ENV PATH /opt/maven/bin:${PATH}
 WORKDIR /cloudwatch_exporter
 COPY . /cloudwatch_exporter
 
-# As of Java 13, the default is POSIX_SPAWN, which doesn't seem to work on
-# ARM64: https://github.com/openzipkin/docker-java/issues/34#issuecomment-721673618
-ENV MAVEN_OPTS "-Djdk.lang.Process.launchMechanism=vfork"
-
 RUN mvn package \
  && mv target/cloudwatch_exporter-*-with-dependencies.jar /cloudwatch_exporter.jar
 
-FROM eclipse-temurin:17-jre-focal as runner
+FROM eclipse-temurin:21-jre-noble as runner
 LABEL maintainer="The Prometheus Authors <prometheus-developers@googlegroups.com>"
 EXPOSE 9106
 

RELEASING.md

@@ -5,7 +5,7 @@ The process is based on the [`java_client` release process](https://github.com/p
 
 ## Requirements
 
-* JDK 17
+* [Temurin JDK 21](https://adoptium.net/)
 * Maven
 * GPG