Test with JDK 21

.github/workflows/gradle.yaml

@@ -128,3 +128,37 @@ jobs:
         with:
           name: jdk17-gradle-${{ matrix.gradle }}-tests
           path: build/reports/tests/test/
+
+  test-gradle-jdk21:
+    needs: linux
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        gradle: [ '8.5' ]
+    steps:
+      - uses: actions/checkout@v3
+
+      - uses: actions/setup-java@v3
+        with:
+          distribution: 'temurin'
+          java-version: |
+            21
+            11
+
+      - name: Setup environment
+        run: |
+          echo "org.gradle.java.installations.auto-download=false" | tee -a gradle.properties
+          echo "org.gradle.java.installations.fromEnv=JAVA_HOME_21_X64" | tee -a gradle.properties
+
+      - name: Build with Gradle
+        id: gradle-build
+        uses: gradle/gradle-build-action@v2
+        with:
+          arguments: --scan test -Ptest.java-toolchain=21 "-Ptest.gradle-version=${{ matrix.gradle }}"
+
+      - name: Store reports
+        if: always() && (steps.gradle-build.outcome == 'success' || steps.gradle-build.outcome == 'failure')
+        uses: actions/upload-artifact@v3
+        with:
+          name: jdk21-gradle-${{ matrix.gradle }}-tests
+          path: build/reports/tests/test/