This chapter includes 11 problems that involve Java functional-style programming. We will start with a problem that's meant to provide a complete journey from 0 to functional interfaces. Then, we will continue by looking at a suite of design patterns from GoF that we will interpret in Java functional style.

By the end of this chapter, you should be familiar with functional-style programming and ready to continue with a set of problems that allow us to deep dive into this topic. You should be able to use a bunch of commonly used design patterns written in functional-style and have a very good understanding of how to evolve code to take advantage of functional interfaces.