Q:

Android SDK Add-On hidden class

I need to export a hidden class through a SDK Add-On in Android Lollipop.  I'm able to export non-hidden classes.  After unsuccessfully trying the "usual way" I thought the problem was due to the @hide tag.  So I decided to try the "dirty" way of getting rid of the @hide keyword responsible to hide the class (even if that would obviously break compatibility with the standard API).  After removing the @hide keyword and building the class with #include(BUILD_JAVA_LIBRARY) in Android.mk, the Java library Jar file is empty.  So I have two questions:

Why the Jar file is empty even if the DEX file includes the class? 
How do I achieve the same result without removing the @hide keyword? 

Thank you. 
Note: I have used these resources as references/documentation: http://elinux.org/images/5/5c/Build_and_Distributing_SDK_Add-Ons.pdf
https://newcircle.com/s/post/1571/exploring_sdk_add_ons_for_android_devices_larry_schiefer_video

A:

I have found a solution by myself and it doesn't really involve the @hide tag.  So I restored the @hide tag.  The @hide tag is meaningful only when building the standard SDK.  Then, I have replaced the package qualified class name, "+package_name.class_name" to export with something like "+package_name.*"  into the Add-On defs file.  After cleaning and rebuilding the Add-On has all the exported classes.