A Functional Approach to Java

Chapter 15. A Functional Approach to Java

Many programming languages support both a functional and imperative code style. However, the syntax and facilities of a language typically incentivize specific approaches to common problems. Even with all the functional additions to the JDK discussed in this book, Java still favors imperative and object-oriented programming, with most of the core libraries’ available types and data structures reflecting this preference.

However, as I’ve discussed throughout this book, that doesn’t mean it has to be an either-or kind of situation. You can augment your OO code with functional principals without going fully functional. Why not have the best of both worlds? To do so, you need to adopt a functional mindset.

This chapter pulls together what you’ve learned in this book so far and highlights the most important aspects that will influence your functional mindset. It also shows a practical application of functional programming techniques on an architectural level that fits right into an object-oriented environment.

OOP Versus FP Principles

To better understand where functional principles can improve your code, it makes sense to revisit the underlying principles of both paradigms—object-oriented and functional—to recognize their dissimilarities and possible interconnection points. This builds the base knowledge to identify opportunities to incorporate a functional approach into your OO code, and where it doesn’t make sense to force it.

Object-oriented ...