using Android.mk I cannot call Java_ functions from MainActivity.java, but using CMakeLists.txt works ok

Question

1. I have created a simple JNI project,
2. I create test.cpp file and inside it I created Java_com_etc_function1()
3. I used CMakeLists.txt to create test.so shared library
4. I loaded the shared library in MainActivity using System.LoadLibrary('test');
5. I called public native void function1() successfully.
6. when I run nm.exe -D test.so , I can confim Java_com_etc_function1() exists.

Everything is ok until I decided to replace the CMakeLists.txt file with Android.mk file.

When ever I change my app gardle file to point to :

ndkBuild {
     path 'src/main/jni/Android.mk'
}

instead of CMakeLists.txt, my project stills build the test.so library, and when I run nm.exe -D test.so I also can confirm that Java_com_etc_function1() exists in it, and am still able to load the library in MainActivity.java , but the problem is : I am not able to call: public native void function1() , its in red color, error: cannot find matching JNI function Java_com_etc_function1() , and when I press Alt + Enter -> choose create function - Nothing happens.

This is my Android.mk file below,

Android.mk file:

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE    := test
LOCAL_EXPORT_LDLIBS := -llog

include $(BUILD_SHARED_LIBRARY)

Application.mk file:

APP_OPTM := release
APP_ABI := all
APP_PLATFORM := android-21

I think I am missing 1 more step to do to be able to call this function from MainActivity.java , but I still can't figure out. Please if you can help me.

Thanks.