First of all I'd like to apologize if this question is to abstract or unsuitable for this site. I really don't know where else to ask.
Currently I have developed apps in iOS and Android. They keep all their state in firebase, so everything is instantly persisted to the Firebase Realtime Database.
Before a user is created I populate the realtime database manually with some data that is expected to be there so that the app can run, such as config data for the user. When I'm "done" using the app I view the data directly in the Firebase console.
Now I want a backend to do the job I have done manually. I want the backend to be able to populate the realtime database and I want it also to be able to retrieve data from Firebase. I would like this to be done from a Java backend(Spring MVC but that might not be critical information right now).
How should I go about doing this? Googling hasn't gotten me that far(java+backend+firebase mostly tells me that "Firebase offers a backend to Android Java").
If this is the wrong place to post this, then please suggest where I can post it instead.
Edit: I am aware of the Server SDK. I am rather referring on how to implement this in what would typically be a stateless rest solution than specifically how the methods in the Server SDK are executed.
Firebase has its own RestApi, you can use it in your api https://firebase.google.com/docs/database/rest/start