Hello Camera2 is an Android Camera2 sample that takes a snapshot using libcamera2ndk.
It uses JNI to access camera2 APIs which recently becomes one of public libraries in Android N.
This fork is a POC that back ports the native camera2 API to Marshmallow and possibly to Lollipop devices.
It runs live camera preview on 6.0.1 Nexus 5 phone, but more experimental data is needed to understand whether it is worth anything beyond a little excercsise in abusing Android system headers.
BTW, the backdoor was slammed shut in Android N, and same techniques are not relevant anymore for modern platforms.
Android Studio 2.3 with NDK bundle. To avoid hassle with old system headers, this project was built with NDK r.14b.
This app sends nothing, shares nothing, and will never do anything beyond being an experimental playground for Android Camera API.