[build] Upgrade to Java 21 (#7547)

Signed-off-by: Jade Turner <spacey-sooty@proton.me>
Co-authored-by: sciencewhiz <sciencewhiz@users.noreply.github.com>

.bazelrc

@@ -10,10 +10,10 @@ common --enable_workspace
 build --experimental_cc_static_library
 build --experimental_cc_shared_library
 
-build --java_language_version=17
-build --java_runtime_version=roboriojdk_17
-build --tool_java_language_version=17
-build --tool_java_runtime_version=remotejdk_17
+build --java_language_version=21
+build --java_runtime_version=remotejdk_21
+build --tool_java_language_version=21
+build --tool_java_runtime_version=remotejdk_21
 
 test --test_output=errors
 test --test_verbose_timeout_warnings

.github/workflows/bazel.yml

@@ -22,8 +22,8 @@ jobs:
         with: { fetch-depth: 0 }
       - uses: actions/setup-java@v4
         with:
-          distribution: 'zulu'
-          java-version: 17
+          distribution: 'temurin'
+          java-version: 21
           architecture: x64
 
       - id: Setup_build_buddy
@@ -42,6 +42,11 @@ jobs:
       - uses: actions/checkout@v4
         with: { fetch-depth: 0 }
 
+      - uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 21
+
       - id: Setup_build_buddy
         uses: ./.github/actions/setup-build-buddy
         with:
@@ -56,7 +61,7 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - { name: "Linux",      os: ubuntu-24.04,   container: "wpilib/ubuntu-base:24.04", action: "test",   config: "",    }
+          - { name: "Linux",      os: ubuntu-24.04,   container: "wpilib/systemcore-cross-ubuntu:2027-24.04", action: "test",   config: "",    }
     name: "${{ matrix.name }}"
     runs-on: ${{ matrix.os }}
     container: ${{ matrix.container }}

.github/workflows/cmake-android.yml

@@ -36,7 +36,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
 
       - name: Install sccache
         uses: mozilla-actions/sccache-action@v0.0.9

.github/workflows/cmake.yml

@@ -18,7 +18,7 @@ jobs:
         include:
           - os: ubuntu-24.04
             name: Linux
-            container: wpilib/roborio-cross-ubuntu:2025-24.04
+            container: wpilib/systemcore-cross-ubuntu:2027-24.04
             flags: "--preset with-java-and-sccache -DCMAKE_BUILD_TYPE=Release -DWITH_EXAMPLES=ON"
           - os: macOS-14
             name: macOS

.github/workflows/documentation.yml

@@ -24,7 +24,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
       - name: Set environment variables (Development)
         run: |
           echo "BRANCH=development" >> $GITHUB_ENV

.github/workflows/gradle.yml

@@ -19,16 +19,16 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - container: wpilib/systemcore-cross-ubuntu:2025-24.04
+          - container: wpilib/systemcore-cross-ubuntu:2027-24.04
             artifact-name: SystemCore
             build-options: "-Ponlylinuxsystemcore"
-          - container: wpilib/raspbian-cross-ubuntu:bookworm-24.04
+          - container: wpilib/raspbian-cross-ubuntu:2027-bookworm-24.04
             artifact-name: Arm32
             build-options: "-Ponlylinuxarm32"
-          - container: wpilib/aarch64-cross-ubuntu:bookworm-24.04
+          - container: wpilib/aarch64-cross-ubuntu:2027-bookworm-24.04
             artifact-name: Arm64
             build-options: "-Ponlylinuxarm64"
-          - container: wpilib/ubuntu-base:24.04
+          - container: wpilib/systemcore-cross-ubuntu:2027-24.04
             artifact-name: Linux
             build-options: "-Ponlylinuxx86-64"
     name: "Build - ${{ matrix.artifact-name }}"
@@ -119,7 +119,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
           architecture: ${{ matrix.architecture }}
       - name: Import Developer ID Certificate
         uses: wpilibsuite/import-signing-certificate@v2
@@ -189,7 +189,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
       - name: Set release environment variable
         run: echo "EXTRA_GRADLE_ARGS=-PreleaseMode" >> $GITHUB_ENV
         if: startsWith(github.ref, 'refs/tags/v2027')
@@ -251,7 +251,7 @@ jobs:
           (github.ref == 'refs/heads/2027' || startsWith(github.ref, 'refs/tags/v2027'))
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
       - name: Combine (2027)
         if: |
           github.repository == 'wpilibsuite/allwpilib' &&

.github/workflows/lint-format.yml

@@ -94,7 +94,7 @@ jobs:
     name: "Java format"
     runs-on: ubuntu-24.04
     needs: [validation]
-    container: wpilib/ubuntu-base:24.04
+    container: wpilib/systemcore-cross-ubuntu:2027-24.04
     steps:
       - uses: actions/checkout@v4
         with:

.github/workflows/sentinel-build.yml

@@ -23,16 +23,16 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - container: wpilib/roborio-cross-ubuntu:2025-24.04
-            artifact-name: Athena
-            build-options: "-Ponlylinuxathena"
-          - container: wpilib/raspbian-cross-ubuntu:bookworm-24.04
+          - container: wpilib/systemcore-cross-ubuntu:2027-24.04
+            artifact-name: SystemCore
+            build-options: "-Ponlylinuxsystemcore"
+          - container: wpilib/raspbian-cross-ubuntu:2027-bookworm-24.04
             artifact-name: Arm32
             build-options: "-Ponlylinuxarm32"
-          - container: wpilib/aarch64-cross-ubuntu:bookworm-24.04
+          - container: wpilib/aarch64-cross-ubuntu:2027-bookworm-24.04
             artifact-name: Arm64
             build-options: "-Ponlylinuxarm64"
-          - container: wpilib/ubuntu-base:24.04
+          - container: wpilib/systemcore-cross-ubuntu:2027-24.04
             artifact-name: Linux
             build-options: "-Ponlylinuxx86-64"
     name: "Build - ${{ matrix.artifact-name }}"
@@ -112,7 +112,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
           architecture: ${{ matrix.architecture }}
       - name: Import Developer ID Certificate
         uses: wpilibsuite/import-signing-certificate@v2

README-CMake.md

@@ -35,7 +35,7 @@ The protobuf library and compiler are needed for protobuf generation.
 
 OpenCV needs to be findable by CMake. On systems like the Jetson, this is installed by default. Otherwise, you will need to build OpenCV from source and install it.
 
-If you want JNI and Java, you will need a JDK of at least version 17 installed. In addition, you need a `JAVA_HOME` environment variable set properly and set to the JDK directory.
+If you want JNI and Java, you will need a JDK of at least version 21 installed. In addition, you need a `JAVA_HOME` environment variable set properly and set to the JDK directory.
 
 If you are building with unit tests or simulation modules, you will also need an Internet connection for the initial setup process, as CMake will clone google-test and imgui from GitHub.
 

README.md

@@ -42,11 +42,11 @@ Using Gradle makes building WPILib very straightforward. It only has a few depen
 
 ## Requirements
 
-- [JDK 17](https://adoptium.net/temurin/releases/?version=17)
+- [JDK 21](https://adoptium.net/temurin/releases/?version=21)
     - Note that the JRE is insufficient; the full JDK is required
-    - On Ubuntu, run `sudo apt install openjdk-17-jdk`
-    - On Windows, install the JDK 17 .msi from the link above
-    - On macOS, install the JDK 17 .pkg from the link above
+    - On Ubuntu, run `sudo apt install openjdk-21-jdk`
+    - On Windows, install the JDK 21 .msi from the link above
+    - On macOS, install the JDK 21 .pkg from the link above
 - C++ compiler
     - On Linux, install GCC 11 or greater
     - On Windows, install [Visual Studio Community 2022](https://visualstudio.microsoft.com/vs/community/) and select the C++ programming language during installation (Gradle can't use the build tools for Visual Studio)

build.gradle

@@ -20,7 +20,7 @@ plugins {
     id 'net.ltgt.errorprone' version '3.1.0' apply false
     id 'com.gradleup.shadow' version '8.3.4' apply false
     id 'com.diffplug.spotless' version '6.20.0' apply false
-    id 'com.github.spotbugs' version '6.0.2' apply false
+    id 'com.github.spotbugs' version '6.1.13' apply false
 }
 
 wpilibVersioning.buildServerMode = project.hasProperty('buildServer')
@@ -111,8 +111,8 @@ subprojects {
 
     plugins.withType(JavaPlugin) {
         java {
-            sourceCompatibility = 17
-            targetCompatibility = 17
+            sourceCompatibility = 21
+            targetCompatibility = 21
         }
     }
 

cameraserver/src/main/java/edu/wpi/first/vision/VisionRunner.java

@@ -73,7 +73,7 @@ public class VisionRunner<P extends VisionPipeline> {
   public void runOnce() {
     Long id = CameraServerSharedStore.getCameraServerShared().getRobotMainThreadId();
 
-    if (id != null && Thread.currentThread().getId() == id) {
+    if (id != null && Thread.currentThread().threadId() == id) {
       throw new IllegalStateException(
           "VisionRunner.runOnce() cannot be called from the main robot thread");
     }
@@ -106,7 +106,7 @@ public class VisionRunner<P extends VisionPipeline> {
   public void runForever() {
     Long id = CameraServerSharedStore.getCameraServerShared().getRobotMainThreadId();
 
-    if (id != null && Thread.currentThread().getId() == id) {
+    if (id != null && Thread.currentThread().threadId() == id) {
       throw new IllegalStateException(
           "VisionRunner.runForever() cannot be called from the main robot thread");
     }

docs/build.gradle

@@ -181,7 +181,7 @@ configurations {
 
 task generateJavaDocs(type: Javadoc) {
     classpath += project(":wpilibj").sourceSets.main.compileClasspath
-    options.links("https://docs.oracle.com/en/java/javase/17/docs/api/")
+    options.links("https://docs.oracle.com/en/java/javase/21/docs/api/")
     options.links("https://docs.opencv.org/4.x/javadoc/")
     options.addStringOption("tag", "pre:a:Pre-Condition")
     options.addBooleanOption("Xdoclint/package:" +

epilogue-processor/src/main/java/edu/wpi/first/epilogue/processor/AnnotationProcessor.java

@@ -40,7 +40,7 @@ import javax.tools.Diagnostic;
   "edu.wpi.first.epilogue.CustomLoggerFor",
   "edu.wpi.first.epilogue.Logged"
 })
-@SupportedSourceVersion(SourceVersion.RELEASE_17)
+@SupportedSourceVersion(SourceVersion.RELEASE_21)
 public class AnnotationProcessor extends AbstractProcessor {
   private static final String kCustomLoggerFqn = "edu.wpi.first.epilogue.CustomLoggerFor";
   private static final String kClassSpecificLoggerFqn =

shared/java/javacommon.gradle

@@ -103,7 +103,7 @@ configurations {
 tasks.withType(JavaCompile).configureEach {
     options.compilerArgs = [
         '--release',
-        '17',
+        '21',
         '-encoding',
         'UTF8',
         "-Werror",

shared/java/javastyle.gradle

@@ -5,7 +5,7 @@ if (project.hasProperty('skipJavaFormat')) {
 apply plugin: 'checkstyle'
 
 checkstyle {
-    toolVersion = "10.12.2"
+    toolVersion = "10.26.1"
     configDirectory = file("${project.rootDir}/styleguide")
     config = resources.text.fromFile(new File(configDirectory.get().getAsFile(), "checkstyle.xml"))
 }

styleguide/checkstyle-suppressions.xml

@@ -16,4 +16,6 @@ suppressions PUBLIC "-//Puppy Crawl//DTD Suppressions 1.1//EN"
     checks="MethodName" />
   <!-- Disable checkstyle for generated unit files -->
   <suppress files="wpiunits[/\\]src[/\\]generated.*" checks=".*"/>
+  <suppress files="wpilibj[/\\]src[/\\]main[/\\]java[/\\]edu[/\\]wpi[/\\]first[/\\]wpilibj[/\\]I2C.java"
+    checks="OverloadMethodsDeclarationOrder" />
 </suppressions>

styleguide/spotbugs-exclude.xml

@@ -37,20 +37,12 @@
     <Bug pattern="IS2_INCONSISTENT_SYNC" />
     <Source name="MechanismLigament2d.java" />
   </Match>
-  <Match>
-    <Bug pattern="MS_CANNOT_BE_FINAL" />
-    <Class name="edu.wpi.first.wpilibj.examples.pacgoat.Robot" />
-  </Match>
   <Match>
     <Bug pattern="MS_EXPOSE_REP" />
   </Match>
   <Match>
     <Bug pattern="MS_MUTABLE_ARRAY" />
   </Match>
-  <Match>
-    <Bug pattern="NM_CLASS_NAMING_CONVENTION" />
-    <Source name="FRCNetComm.java" />
-  </Match>
   <Match>
     <Bug pattern="NS_DANGEROUS_NON_SHORT_CIRCUIT" />
     <Source name="ParallelCommandGroup.java" />
@@ -156,4 +148,12 @@
     <Bug pattern="UUF_UNUSED_PUBLIC_OR_PROTECTED_FIELD" />
     <Class name="edu.wpi.first.epilogue.EpilogueConfiguration" />
   </Match>
+  <Match>
+    <Bug pattern="SING_SINGLETON_HAS_NONPRIVATE_CONSTRUCTOR" />
+    <Class name="edu.wpi.first.wpilibj2.command.CommandScheduler" />
+  </Match>
+  <Match>
+    <Bug pattern="SING_SINGLETON_HAS_NONPRIVATE_CONSTRUCTOR" />
+    <Class name="~edu.wpi.first.math.geometry.Coordinate\w+" />
+  </Match>
 </FindBugsFilter>

wpilibj/src/main/java/edu/wpi/first/wpilibj/RobotBase.java

@@ -93,7 +93,7 @@ public abstract class RobotBase implements AutoCloseable {
    */
   protected RobotBase() {
     final NetworkTableInstance inst = NetworkTableInstance.getDefault();
-    m_threadId = Thread.currentThread().getId();
+    m_threadId = Thread.currentThread().threadId();
     setupCameraServerShared();
     setupMathShared();
     // subscribe to "" to force persistent values to propagate to local

wpiutil/src/main/java/edu/wpi/first/util/struct/StructGenerator.java

@@ -435,7 +435,6 @@ public final class StructGenerator {
     }
 
     int size = 0;
-    boolean failed = false;
 
     for (final E constant : enumVariants) {
       final String name = constant.name();
@@ -452,6 +451,8 @@ public final class StructGenerator {
             .filter(f -> !f.isEnumConstant() && !Modifier.isStatic(f.getModifiers()))
             .toList();
 
+    boolean failed = false;
+
     for (final Field field : enumFields) {
       final Class<?> type = field.getType();
       final String name = field.getName();