Summary
In this chapter, we've looked at some of the functional programming principles and terms. We've learned how to write programs composed of small pure function actions, chained together using higher order functions.
As functional programming is getting increasingly popular, developers proficient in it will be in high demand in the very near future. That's because it helps us achieve scalability and parallelism with ease. And what is more, if we add the reactive idea to it, it becomes even more appealing.
That's why we are going to dive into the RxJava framework in the next chapters, learning how to use it for our benefit. We'll begin with the Observable
instance creation techniques. This will provide us with the skill to create an Observable
instance from everything, thus turning almost everything into a functional reactive program.