How to user Firebase for java web server?

I want to do an android app. For this, i founded Firebase and it worked when i tested for what i want. But, i need to do an web server; i want to do in Java, because is more easy for me, i do not know Javascript, and i don't have time to learn this (i know is not really hard, but already i have the code wrote in Java). My problem is i didn't find anything how to integrate firebase in my java web project. Is not possible to do this? How to do, where i can found more documentation? I apreciate all answers!!