In this chapter, we touched on various parts of the rich RxAndroid ecosystem to build reactive Android applications. We covered Retrolambda so that we can leverage lambdas with earlier versions of Android that only support Java 6. This way, we do not have to resort to anonymous inner classes to express our RxJava operators. We also touched on RxAndroid, which is the core of the reactive Android ecosystem, and it only contains Android schedulers. To plug in your various Android widgets, controls, and domain-specific events, you will need to rely on other libraries, such as RxBinding.
In the next chapter, you will learn how to use RxJava with Kotlin—an exciting new language that has essentially become the Swift of Android. You will learn the basics of Kotlin and why it works so well with RxJava.