Always test on the latest Java (#1819)

Author: Goooler

.github/renovate.json5

@@ -22,5 +22,25 @@
         "com.gradle.develocity:com.gradle.develocity.gradle.plugin",
       ],
     },
+  ],
+  ignorePresets: [
+    // Ensure we get the latest version and are not pinned to old versions.
+    'workarounds:javaLTSVersions',
+  ],
+  customManagers: [
+    // Update .java-version file with the latest JDK version.
+    {
+      customType: 'regex',
+      fileMatch: [
+        '\\.java-version$',
+      ],
+      matchStrings: [
+        '(?<currentValue>.*)\\n',
+      ],
+      datasourceTemplate: 'java-version',
+      depNameTemplate: 'java',
+      // Only write the major version.
+      extractVersionTemplate: '^(?<version>\\d+)',
+    },
   ]
 }

.github/workflows/.java-version

@@ -0,0 +1 @@
+24

.github/workflows/build.yml

@@ -9,29 +9,19 @@ 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, 24 ]
+        os: [ ubuntu-24.04-arm, windows-latest ]
         # Test on the minimum Gradle version and the latest.
         gradle: [ 9.0.0, current ]
-        include:
-          # We just test one JDK version on Windows.
-          - os: windows-11-arm
-            gradle: 9.0.0
-            java: 21
-          - os: windows-11-arm
-            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 -x lint
 
@@ -43,7 +33,7 @@ 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
       - run: ./gradlew lint
 
@@ -73,7 +63,7 @@ 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

@@ -18,7 +18,7 @@ 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