Sir,
I am a CSE Graduate,and I make android apps using Java Native Android Development
Some example are,
Quarkus RestApi Aondroid app that can read,write,put,post http Requests and data,
Clone WhatsApp that has implementations like saving user data,registration data,UI implementation for Registraoin,Show Info,Chat ,ListUsers etc attributes saved in #Firebase..
Check My Freelancer Profile For Demo Videos:
https://www.freelancer.com/u/Asif296