How to call core method from android backend?

I can use android methods from GDX (Platform specific code), but is it possible to get libgdx method from android back-end? I have firebase database. On android side of my game I catch any changes in database. And I need to transfer that changes to my core back-end (For example update some actors, labels, and so on). What's the best way to do that?

Accessing Platform Specific API inside core module can be possible using Interfacing.

core-module is common part of all platform so you can access anywhere in your project.

Keep reference of ApplicationListener, If you want to call any method/access data member of your core module.

Inside android module :

public class AndroidLauncher extends AndroidApplication {

    MyGdxGame gdxGame;

    @Override
    protected void onCreate (Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        AndroidApplicationConfiguration config = new AndroidApplicationConfiguration();

        gdxGame=new MyGdxGame();
        initialize(gdxGame, config);
    }

     public void andoridMethod(){
         System.out.println(gdxGame.x);      //access data member
         gdxGame.doSomething();              //access method
     }
}

Inside core module :

public class MyGdxGame implements ApplicationListener {

      public int x=4;

      public void doSomething(){}

      // Life cycle methods of ApplicationListener
}