explicit set an "optional" tag
diff --git a/Android.mk b/Android.mk
index 068ee1c..b4b44dd 100644
--- a/Android.mk
+++ b/Android.mk
@@ -17,7 +17,7 @@
 LOCAL_PATH := $(call my-dir)
 include $(CLEAR_VARS)
 
-# LOCAL_MODULE_TAGS := user
+LOCAL_MODULE_TAGS := optional
 
 LOCAL_SRC_FILES := $(call all-subdir-java-files)