Simplify CI matrix to use latest Gradle version per Java version

- Reduce matrix from 13 combinations to 5 (one per Java version)
- Use Gradle 8.14.3 for Java 8, 11, 17 (latest 8.x)
- Use Gradle 9.2.1 for Java 21, 25 (latest 9.x)
- Add Gradle setup step using gradle-build-action
- Add compatibility validation step as safety check
- Update Gradle wrapper to match matrix version
- Improve caching with Gradle version in cache key
- Update artifact names to include both Java and Gradle versions

Author: gamma

.github/workflows/ci.yml

@@ -8,13 +8,26 @@ on:
 
 jobs:
   build:
-    name: Build and Test (JDK ${{ matrix.java-version }})
+    name: Build and Test (JDK ${{ matrix.java-version }}, Gradle ${{ matrix.gradle-version }})
     runs-on: ubuntu-latest
 
     strategy:
       fail-fast: false  # Don't cancel other jobs if one fails
       matrix:
-        java-version: ['8', '11', '17', '21', '25']
+        include:
+          # Use latest Gradle version that supports each Java version
+          # Java 8, 11, 17: Latest Gradle 8.x (8.14.3 supports Java 8-21)
+          - java-version: '8'
+            gradle-version: '8.14.3'
+          - java-version: '11'
+            gradle-version: '8.14.3'
+          - java-version: '17'
+            gradle-version: '8.14.3'
+          # Java 21, 25: Latest Gradle 9.x (9.2.1 supports Java 19-25)
+          - java-version: '21'
+            gradle-version: '9.2.1'
+          - java-version: '25'
+            gradle-version: '9.2.1'
 
     steps:
       - name: Checkout code
@@ -31,16 +44,62 @@ jobs:
         with:
           node-version: '18'
 
+      - name: Setup Gradle ${{ matrix.gradle-version }}
+        uses: gradle/gradle-build-action@v2
+        with:
+          gradle-version: ${{ matrix.gradle-version }}
+      
+      - name: Validate Gradle-Java compatibility
+        run: |
+          JAVA_VERSION=${{ matrix.java-version }}
+          GRADLE_VERSION="${{ matrix.gradle-version }}"
+          
+          echo "Checking compatibility: Java $JAVA_VERSION with Gradle $GRADLE_VERSION"
+          
+          # Gradle 7.x supports Java 8-19
+          if [[ "$GRADLE_VERSION" == 7.* ]]; then
+            if [[ "$JAVA_VERSION" -ge 8 && "$JAVA_VERSION" -le 19 ]]; then
+              echo "✓ Compatible: Gradle 7.x supports Java 8-19"
+            else
+              echo "✗ Incompatible: Gradle 7.x requires Java 8-19, but Java $JAVA_VERSION is specified"
+              exit 1
+            fi
+          # Gradle 8.x supports Java 8-21
+          elif [[ "$GRADLE_VERSION" == 8.* ]]; then
+            if [[ "$JAVA_VERSION" -ge 8 && "$JAVA_VERSION" -le 21 ]]; then
+              echo "✓ Compatible: Gradle 8.x supports Java 8-21"
+            else
+              echo "✗ Incompatible: Gradle 8.x requires Java 8-21, but Java $JAVA_VERSION is specified"
+              exit 1
+            fi
+          # Gradle 9.x supports Java 19-25
+          elif [[ "$GRADLE_VERSION" == 9.* ]]; then
+            if [[ "$JAVA_VERSION" -ge 19 && "$JAVA_VERSION" -le 25 ]]; then
+              echo "✓ Compatible: Gradle 9.x supports Java 19-25"
+            else
+              echo "✗ Incompatible: Gradle 9.x requires Java 19-25, but Java $JAVA_VERSION is specified"
+              exit 1
+            fi
+          else
+            echo "⚠ Unknown Gradle version: $GRADLE_VERSION"
+          fi
+        shell: bash
+      
       - name: Cache Gradle dependencies
         uses: actions/cache@v3
         with:
           path: |
             ~/.gradle/caches
             ~/.gradle/wrapper
-          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*') }}
+          key: ${{ runner.os }}-gradle-${{ matrix.gradle-version }}-${{ hashFiles('**/*.gradle*') }}
           restore-keys: |
+            ${{ runner.os }}-gradle-${{ matrix.gradle-version }}-
             ${{ runner.os }}-gradle-
       
+      - name: Update Gradle wrapper
+        run: gradle wrapper --gradle-version ${{ matrix.gradle-version }} --no-daemon
+        shell: bash
+      
       - name: Build and test with benchmarks
         run: ./gradlew -Djdk.tls.client.protocols="TLSv1,TLSv1.1,TLSv1.2" --stacktrace check benchmark
         shell: bash
@@ -49,20 +108,20 @@ jobs:
         if: always()
         uses: actions/upload-artifact@v4
         with:
-          name: test-results-jdk${{ matrix.java-version }}
+          name: test-results-jdk${{ matrix.java-version }}-gradle${{ matrix.gradle-version }}
           path: build/test-results/
           retention-days: 7
 
       - name: Upload coverage reports
         if: always()
         uses: actions/upload-artifact@v4
         with:
-          name: coverage-reports-jdk${{ matrix.java-version }}
+          name: coverage-reports-jdk${{ matrix.java-version }}-gradle${{ matrix.gradle-version }}
           path: build/reports/jacoco/
           retention-days: 7
 
       - name: Upload build artifacts
-        if: matrix.java-version == '11'
+        if: matrix.java-version == '11' && matrix.gradle-version == '8.14.3'
         uses: actions/upload-artifact@v4
         with:
           name: build-artifacts