Set up Java before we invoke compile.

.github/workflows/codeql.yml

@@ -28,15 +28,15 @@ jobs:
       actions: read
       contents: read
 
-    strategy:
-      fail-fast: false
-      matrix:
-        language: [ 'java-kotlin' ]
-
     steps:
     - name: Checkout repository
       uses: actions/checkout@v4
 
+    - uses: actions/setup-java@v4
+      with:
+        distribution: 'zulu'
+        java-version: '20'
+
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v3