diff --git a/.github/workflows/gradle.yml b/.github/workflows/gradle.yml
index 59ab483..672048a 100644
--- a/.github/workflows/gradle.yml
+++ b/.github/workflows/gradle.yml
@@ -13,6 +13,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - name: Checkout submodules
+      run: git submodule update --init --recursive
     - name: Set up JDK 8
       uses: actions/setup-java@v2
       with: