diff --git a/java/BUCK b/java/BUCK
index d08cb37b..a658d7e9 100644
--- a/java/BUCK
+++ b/java/BUCK
@@ -1,3 +1,5 @@
+# BUILD FILE SYNTAX: PYTHON_DSL
+
 # Copyright (c) Facebook, Inc. and its affiliates.
 #
 # This source code is licensed under the MIT license found in the