Set up JDK 1.8

.github/workflows/ci.yml

@@ -32,6 +32,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - name: set up JDK 1.8
+        uses: actions/setup-java@v1
+        with:
+          java-version: 1.8
+      - name: Install NDK 21
+        run: echo "y" | sudo /usr/local/lib/android/sdk/tools/bin/sdkmanager --install "ndk;21.0.6113669" "ndk;20.0.5594570" --sdk_root=${ANDROID_SDK_ROOT}
       - name: Install dependencies
         run: |
           if [[ -n "${{ secrets.encrypted_d27e803291ff_iv }}" ]]; then