package com.bookcrossing.mobile.modules;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.storage.FirebaseStorage;

import javax.inject.Singleton;

import dagger.Module;
import dagger.Provides;

/** (c) 2016 Andrey Mukamolow aka fobo66 <fobo66@protonmail.com>
 * Created by fobo66 on 15.11.2016.
 */

@Module
public class ApiModule {

    @Provides
    @Singleton
    public FirebaseDatabase provideDatabase() {
        return FirebaseDatabase.getInstance();
    }

    @Provides
    @Singleton
    public FirebaseStorage provideStorage() {
        return FirebaseStorage.getInstance();
    }

    @Provides
    @Singleton
    public FirebaseAuth provideAuth() {
        return FirebaseAuth.getInstance();
    }

}

package com.bookcrossing.mobile.modules;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.storage.FirebaseStorage;

import dagger.Module;
import dagger.Provides;

/** (c) 2016 Andrey Mukamolow aka fobo66 <fobo66@protonmail.com>
 * Created by fobo66 on 15.11.2016.
 */

@Module
public class ApiModule {

    @Provides
    public FirebaseDatabase provideDatabase() {
        return FirebaseDatabase.getInstance();
    }

    @Provides
    public FirebaseStorage provideStorage() {
        return FirebaseStorage.getInstance();
    }

    @Provides
    public FirebaseAuth provideAuth() {
        return FirebaseAuth.getInstance();
    }

}

Remove @Singletone annotation from API for better performance
Remove @Singletone annotation from API for better performance
