C++, Android Java programming skills
Deep understanding of Android AOSP and difference between various Android version from AOSP point of view
VNDK, Trible architecture for HAL
Understanding of Android Systems services
JNI, AIDL understanding and communication methods between the various Android layers
Android build system understanding and also Gradle build system for Apps
Android App framework understanding, App life cycle management
Android overlays
Android on Hypervisor environment understanding and virtual IO communication understanding