Update to Java 21

.azure/templates/jobs/build_java.yaml

@@ -4,9 +4,9 @@ jobs:
     # Strategy for the job
     strategy:
       matrix:
-        'java-17':
+        'java-21':
           image: 'Ubuntu-22.04'
-          jdk_version: '17'
+          jdk_version: '21'
     # Set timeout for jobs
     timeoutInMinutes: 60
     # Base system

.azure/templates/jobs/deploy_java.yaml

@@ -6,9 +6,9 @@ jobs:
     # Strategy for the job
     strategy:
       matrix:
-        'java-17':
+        'java-21':
           image: 'Ubuntu-22.04'
-          jdk_version: '17'
+          jdk_version: '21'
     # Base system
     pool:
       vmImage: $(image)

.azure/templates/jobs/run_systemtests.yaml

@@ -7,7 +7,7 @@ jobs:
           ${{ arch }}:
             arch: ${{ arch }}
             image: 'Ubuntu-22.04'
-            jdk_version: '17'
+            jdk_version: '21'
     pool:
       vmImage: $(image)
     variables:

.azure/templates/steps/prerequisites/install_java.yaml

@@ -1,7 +1,7 @@
 # Step to configure JAVA on the agent
 parameters:
   - name: JDK_VERSION
-    default: '17'
+    default: '21'
 steps:
   - task: JavaToolInstaller@0
     inputs:

.checkstyle/checkstyle.xml

@@ -104,6 +104,38 @@
 
         <!-- Make the @SuppressWarnings annotations available to Checkstyle -->
         <module name="SuppressWarningsHolder" />
+
+        <!-- Javadocs -->
+        <module name="MissingJavadocType">
+            <!-- public types -->
+            <property name="scope" value="public" />
+        </module>
+        <module name="MissingJavadocMethod">
+            <!-- public methods -->
+            <property name="scope" value="public" />
+        </module>
+        <module name="JavadocType">
+            <!-- public types -->
+            <property name="scope" value="public" />
+        </module>
+        <module name="JavadocVariable">
+            <!-- public variables -->
+            <property name="scope" value="public" />
+        </module>
+        <module name="JavadocMethod">
+            <!-- public methods -->
+            <property name="accessModifiers" value="public" />
+        </module>
+        <module name="JavadocBlockTagLocation" />
+        <module name="JavadocContentLocation" />
+        <module name="JavadocLeadingAsteriskAlign" />
+        <module name="JavadocMissingLeadingAsterisk" />
+        <module name="JavadocMissingWhitespaceAfterAsterisk" />
+        <module name="JavadocStyle">
+            <property name="checkEmptyJavadoc" value="true"/>
+            <property name="checkFirstSentence" value="false"/>
+        </module>
+        <module name="NonEmptyAtclauseDescription"/>
     </module>
 
     <module name="SuppressionFilter">

.checkstyle/suppressions.xml

@@ -14,4 +14,10 @@
          In all other cases, you should use the annotations on the methods or classes affected by it. -->
     <suppress checks=".*"
               files="io[/\\]strimzi[/\\]kafka[/\\]access[/\\]model[/\\].*(Builder|Fluent|FluentImpl)\.java"/>
+
+    <!-- Skip Javadoc checks for tests -->
+    <suppress checks="(JavadocMethod|JavadocType|JavadocVariable|MissingJavadocType|MissingJavadocMethod)" files="src[/\\]test[/\\]java[/\\].*"/>
+
+    <!-- Skip Javadoc checks for systemtests -->
+    <suppress checks="(JavadocMethod|JavadocType|JavadocVariable|MissingJavadocType|MissingJavadocMethod|JavadocStyle)" files="systemtest[/\\]src[/\\]main[/\\]java[/\\].*"/>
 </suppressions>

.github/actions/build/build-binaries/action.yml

@@ -13,7 +13,7 @@ runs:
     - name: Setup Java
       uses: strimzi/strimzi-kafka-operator/.github/actions/dependencies/setup-java@main
       with:
-        javaVersion: "17"
+        javaVersion: "21"
 
     - name: Setup Yq
       uses: strimzi/strimzi-kafka-operator/.github/actions/dependencies/install-yq@main

.github/actions/build/deploy-java/action.yml

@@ -25,7 +25,7 @@ runs:
     - name: Setup Java and Maven
       uses: strimzi/strimzi-kafka-operator/.github/actions/dependencies/setup-java@main
       with:
-        javaVersion: "17"
+        javaVersion: "21"
 
     - name: Restore Maven cache
       uses: actions/cache/restore@v5

.github/actions/build/release-artifacts/action.yml

@@ -28,7 +28,7 @@ runs:
     - name: Setup Java
       uses: strimzi/strimzi-kafka-operator/.github/actions/dependencies/setup-java@main
       with:
-        javaVersion: "17"
+        javaVersion: "21"
 
     - name: Install Helm
       uses: strimzi/strimzi-kafka-operator/.github/actions/dependencies/install-helm@main

.github/actions/build/run-systemtests/action.yml

@@ -21,7 +21,7 @@ runs:
     - name: Setup Java
       uses: strimzi/strimzi-kafka-operator/.github/actions/dependencies/setup-java@main
       with:
-        javaVersion: "17"
+        javaVersion: "21"
 
     - name: Setup Kind
       uses: strimzi/strimzi-kafka-operator/.github/actions/dependencies/setup-kind@main

.github/workflows/codeql-analysis.yml

@@ -46,7 +46,7 @@ jobs:
     - name: Setup java
       uses: actions/setup-java@v5
       with:
-        java-version: 17
+        java-version: 21
         distribution: 'temurin'
         cache: 'maven'
 

Dockerfile

@@ -1,5 +1,5 @@
 FROM registry.access.redhat.com/ubi9/ubi-minimal:latest
-ARG JAVA_VERSION=17
+ARG JAVA_VERSION=21
 ARG TARGETPLATFORM
 
 USER root
@@ -9,7 +9,7 @@ RUN microdnf update -y \
     && microdnf clean all -y
 
 # Set JAVA_HOME env var
-ENV JAVA_HOME=/usr/lib/jvm/jre-17
+ENV JAVA_HOME=/usr/lib/jvm/jre-${JAVA_VERSION}
 
 # Add strimzi user with UID 1001
 # The user is in the group 0 to have access to the mounted volumes and storage

api/pom.xml

@@ -12,14 +12,6 @@
     <name>Strimzi Access Operator - API</name>
     <artifactId>api</artifactId>
 
-    <properties>
-        <maven.compiler.source>17</maven.compiler.source>
-        <maven.compiler.target>17</maven.compiler.target>
-        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-
-        <javadoc.fail.on.warnings>false</javadoc.fail.on.warnings>
-    </properties>
-
     <dependencies>
         <dependency>
             <groupId>io.fabric8</groupId>

api/src/main/java/io/strimzi/kafka/access/model/KafkaAccessStatus.java

@@ -87,6 +87,11 @@ public long getObservedGeneration() {
         return observedGeneration;
     }
 
+    /**
+     * Sets the observed generation of the KafkaAccess resource.
+     *
+     * @param observedGeneration The observed generation to set.
+     */
     public void setObservedGeneration(long observedGeneration) {
         this.observedGeneration = observedGeneration;
     }

development-docs/DEV_GUIDE.md

@@ -42,17 +42,17 @@ can do `brew install gnu-sed findutils grep coreutils`.
 This command will install the GNU versions as `gcp`, `ggrep`, `gsed` and `gfind` and our `make` build will automatically pick them up and use them.
 
 The `mvn` tool might install the latest version of OpenJDK during the brew install. For builds on macOS to succeed,
-OpenJDK version 17 needs to be installed. This can be done by running `brew install openjdk@17`. For maven to read the
+OpenJDK version 21 needs to be installed. This can be done by running `brew install openjdk@21`. For maven to read the
 new Java version, you will need to edit the `~/.mavenrc` file and paste the following
-line `export JAVA_HOME=/Library/Java/JavaVirtualMachines/openjdk-17.jdk/Contents/Home`.
+line `export JAVA_HOME=/Library/Java/JavaVirtualMachines/openjdk-21.jdk/Contents/Home`.
 
 You may come across an issue of linking from the above step. To solve this run this command:
-`sudo ln -sfn /usr/local/opt/openjdk@17/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk-17.jdk`.
+`sudo ln -sfn /usr/local/opt/openjdk@21/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk-21.jdk`.
 If this throws an error that it cannot find the file or directory, navigate into `/Library/Java/` (or however deep you
-can) and create a new folder named `JavaVirtualMachines` followed by creating a file named `openjdk-17.jdk`. The folder
-structure after everything is said and done should look like `/Library/Java/JavaVirtualMachines/openjdk-17.jdk`. After
+can) and create a new folder named `JavaVirtualMachines` followed by creating a file named `openjdk-21.jdk`. The folder
+structure after everything is said and done should look like `/Library/Java/JavaVirtualMachines/openjdk-21.jdk`. After
 doing that run the command at the beginning again and this should link the file and allow you to use maven with OpenJDK
-version 17.
+version 21.
 
 ## Run Pre-Requisites
 
@@ -173,10 +173,7 @@ the `strimzi` organization with the tag latest).
 
 ### Java versions
 
-To use different Java version for the Maven build, you can specify the environment variable `JAVA_VERSION_BUILD` and set
-it to the desired Java version. For example, for building with Java 17 you can use `export JAVA_VERSION_BUILD=17`.
-
-> *Note*: Operator currently developed and tested with Java 17.
+The operator requires Java 21 for building. The build uses Java 21 by default.
 
 ### Java build options
 
@@ -192,11 +189,9 @@ example:
 
 When building the Docker images you can use an alternative JRE or use an alternate base image.
 
-#### Alternative Docker image JRE
+#### Docker image JRE
 
-The docker images can be built with an alternative Java version by setting the environment variable `JAVA_VERSION`. For
-example, to build docker images that have the Java 17 JRE installed use `JAVA_VERSION=17 make docker_build`. If not
-present, the container images will use Java **17** by default.
+The container images use Java **21**.
 
 #### Alternative `docker` command
 

operator/pom.xml

@@ -11,12 +11,6 @@
     <name>Strimzi Access Operator</name>
     <artifactId>operator</artifactId>
 
-    <properties>
-        <maven.compiler.source>17</maven.compiler.source>
-        <maven.compiler.target>17</maven.compiler.target>
-        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    </properties>
-
     <dependencies>
         <dependency>
             <groupId>io.javaoperatorsdk</groupId>

operator/src/main/java/io/strimzi/kafka/access/KafkaAccessReconciler.java

@@ -59,6 +59,8 @@ public class KafkaAccessReconciler implements Reconciler<KafkaAccess> {
     public static final String KAFKA_USER_SECRET_EVENT_SOURCE = "KAFKA_USER_SECRET_EVENT_SOURCE";
 
     /**
+     * Creates a new KafkaAccessReconciler.
+     *
      * @param kubernetesClient      The Kubernetes client
      */
     public KafkaAccessReconciler(final KubernetesClient kubernetesClient) {

pom.xml

@@ -50,20 +50,20 @@
     <properties>
         <!-- Build dependencies -->
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <maven.compiler.source>17</maven.compiler.source>
-        <maven.compiler.target>17</maven.compiler.target>
-        <maven.checkstyle.version>3.1.2</maven.checkstyle.version>
-        <maven.compiler.version>3.8.1</maven.compiler.version>
-        <checkstyle.version>9.0.1</checkstyle.version>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
+        <maven.checkstyle.version>3.5.0</maven.checkstyle.version>
+        <maven.compiler.version>3.13.0</maven.compiler.version>
+        <checkstyle.version>10.18.1</checkstyle.version>
         <maven.surefire.version>3.2.2</maven.surefire.version>
         <maven.failsafe.version>3.2.2</maven.failsafe.version>
         <maven.license.version>2.11</maven.license.version>
-        <spotbugs.version>4.5.3</spotbugs.version>
-        <spotbugs-maven-plugin.version>4.5.3.0</spotbugs-maven-plugin.version>
+        <spotbugs.version>4.8.6</spotbugs.version>
+        <spotbugs-maven-plugin.version>4.8.6.4</spotbugs-maven-plugin.version>
         <maven.javadoc.version>3.5.0</maven.javadoc.version>
         <maven.source.version>3.3.1</maven.source.version>
         <maven.shade.version>3.1.0</maven.shade.version>
-        <maven.dependency.version>3.3.0</maven.dependency.version>
+        <maven.dependency.version>3.9.0</maven.dependency.version>
         <maven.assembly.version>3.3.0</maven.assembly.version>
         <maven.gpg.version>3.0.1</maven.gpg.version>
         <central-publishing-maven-plugin.version>0.7.0</central-publishing-maven-plugin.version>
@@ -92,7 +92,7 @@
         <helm-client.version>0.0.18</helm-client.version>
         <hamcrest.version>2.2</hamcrest.version>
 
-        <javadoc.fail.on.warnings>true</javadoc.fail.on.warnings>
+        <javadoc.fail.on.warnings>false</javadoc.fail.on.warnings>
 
         <!-- failsafe fork-count configuration -->
         <failsafe.forkCount>1</failsafe.forkCount>

systemtest/pom.xml

@@ -13,11 +13,6 @@
     <artifactId>systemtest</artifactId>
 
     <properties>
-        <maven.compiler.source>17</maven.compiler.source>
-        <maven.compiler.target>17</maven.compiler.target>
-        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <javadoc.fail.on.warnings>false</javadoc.fail.on.warnings>
-
         <skipTests>true</skipTests>
     </properties>