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

MarvelApplicationImpl.java

package com.mirhoseini.marvel;

import timber.log.Timber;

public class MarvelApplicationImpl extends MarvelApplication {

    @Override
    public void initApplication() {

        // initialize Timber in debug version to log
        Timber.plant(new Timber.DebugTree() {
            @Override
            protected String createStackElementTag(StackTraceElement element) {
                // adding line number to logs
                return super.createStackElementTag(element) + ":" + element.getLineNumber();
            }
        });

    }
}