Sample Application class https://hackernoon.com/yet-another-mvp-article-part-2-how-dagger-helps-with-the-project-90d049a45e00

MarvelApplication.java

package com.mirhoseini.marvel;

import android.app.Application;

public abstract class MarvelApplication extends Application {

    private static ApplicationComponent component;

    public static ApplicationComponent getComponent() {
        return component;
    }

    @Override
    public void onCreate() {
        super.onCreate();

        initApplication();

        component = createComponent();
    }

    public ApplicationComponent createComponent() {
        return DaggerApplicationComponent.builder()
                .androidModule(new AndroidModule(this))
                .build();
    }

    public abstract void initApplication();

}