diff --git a/lib/github-actions-metadata-update.sh b/lib/github-actions-metadata-update.sh
index dcada31b5..4dc462ee8 100644
--- a/lib/github-actions-metadata-update.sh
+++ b/lib/github-actions-metadata-update.sh
@@ -82,6 +82,12 @@ PREVIOUS=$(git describe --abbrev=0)
 
 FILES=$(getReleaseDelta google/libphonenumber "v${DEPLOYED_NUGET_TAG}" $UPSTREAM_GITHUB_RELEASE_TAG)
 
+if echo $FILES | grep '\.java'
+then
+   echo "has java files, automatic update not possible"
+   exit 123
+fi
+
 if echo $FILES | grep 'proto'
 then
    echo "has proto files, automatic update not possible"