Always run CI on the latest Java

.github/workflows/.java-version

@@ -0,0 +1 @@
+25

.github/workflows/ci.yml

@@ -11,32 +11,19 @@ on:
 
 jobs:
   build:
-    name: OS=${{ matrix.os }}, Java=${{ matrix.java }}, Gradle=${{ matrix.gradle }}
+    name: OS=${{ matrix.os }}, Gradle=${{ matrix.gradle }}
     strategy:
       matrix:
-        os: [ ubuntu-24.04-arm ]
-        # Always test on the latest version and some LTS.
-        java: [ 17, 25 ]
+        os: [ ubuntu-24.04-arm, windows-latest ]
         # Test on the minimum Gradle version and the latest.
         gradle: [ 8.3, current ]
-        exclude:
-          # Gradle 8.3 doesn't support Java 25.
-          - gradle: 8.3
-            java: 25
-        include:
-          - os: windows-latest
-            gradle: 8.3
-            java: 17
-          - os: windows-latest
-            gradle: current
-            java: 21
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v5
       - uses: actions/setup-java@v5
         with:
           distribution: 'zulu'
-          java-version: ${{ matrix.java }}
+          java-version-file: .github/workflows/.java-version
       - uses: gradle/actions/setup-gradle@v5
       - run: ./gradlew build "-PtestGradleVersion=${{ matrix.gradle }}" --stacktrace
 
@@ -65,7 +52,7 @@ jobs:
       - uses: actions/setup-java@v5
         with:
           distribution: 'zulu'
-          java-version: 21
+          java-version-file: .github/workflows/.java-version
       - uses: gradle/actions/setup-gradle@v5
         with:
           cache-read-only: true

.github/workflows/release.yml

@@ -16,7 +16,7 @@ jobs:
       - uses: actions/setup-java@v5
         with:
           distribution: 'zulu'
-          java-version: 21
+          java-version-file: .github/workflows/.java-version
       - uses: gradle/actions/setup-gradle@v5
         with:
           cache-read-only: true