diff --git a/Android.mk b/Android.mk
index 7f1871a..0131adc 100644
--- a/Android.mk
+++ b/Android.mk
@@ -3,7 +3,8 @@
 
 LOCAL_MODULE_TAGS := user
 
-LOCAL_SRC_FILES := $(call all-subdir-java-files)
+# Only compile source java files in this apk.
+LOCAL_SRC_FILES := $(call all-java-files-under, src)
 
 LOCAL_JAVA_LIBRARIES := ext