Merge pull request #442 from apache/setup-java-action

explicit java setup
diff --git a/.github/workflows/serde_compat.yml b/.github/workflows/serde_compat.yml
index cdc2fc5..3c137f6 100644
--- a/.github/workflows/serde_compat.yml
+++ b/.github/workflows/serde_compat.yml
@@ -18,6 +18,10 @@
         with:
           repository: apache/datasketches-java
           path: java
+      - name: Setup Java
+        uses: actions/setup-java@v2
+        with:
+          java-version: '11'
       - name: Run Java
         run: cd java && mvn test -P generate-java-files
       - name: Copy files