Run tests against all modern Java version in pipeline

Author: basdijkstra

.github/workflows/ci.yml

@@ -3,15 +3,22 @@ name: Java CI
 on: [push]
 
 jobs:
-  build:
+  run-the-tests:
     runs-on: ubuntu-latest
 
+    strategy:
+      matrix:
+        java-version: [ '17', '21', '22', '23', '24' ]
+      fail-fast: false
+
     steps:
       - uses: actions/checkout@v4
-      - name: Set up JDK 21
+      - name: Set up JDK ${{ matrix.java-version }}
         uses: actions/setup-java@v4
         with:
-          java-version: '21'
+          java-version: ${{ matrix.java-version }}
           distribution: 'temurin'
+      - name: Check active Java version
+        run: javac -version
       - name: Run tests in answers package
         run: mvn clean "-Dtest=answers.*Test" test