Authenticate users in Java AppEngine Application with Firebase

Question

First I build an AppEngine with java, that uses the Google Sign-In library: https://cloud.google.com/appengine/docs/standard/java/users/

But now we want to also have an android app and switch from Google Sign-In to Firebase (because it integrates way better with android).

Unfortunately, I found no java sdk for firebase that would replace the Google Sign-In probably.

What is the best way, to add firebase authentication to a java AppEngine application?

Answer 1

Java has REST capabilities. Use Firebase Auth REST API.