Part 6. Functional programming and future Java evolution

In the final part of this book, we draw back a little with a tutorial introduction to writing effective functional-style programs in Java, along with a comparison of Java 8 features with those of Scala.

Chapter 18 gives a full tutorial on functional programming, introduces some of its terminology, and explains how to write functional-style programs in Java.

Chapter 19 covers more advanced functional programming techniques including higher-order functions, currying, persistent data structures, lazy lists, and pattern matching. You can view this chapter as a mix of practical techniques to apply in your codebase as well as academic information that will make you a more knowledgeable programmer.

Chapter 20 follows by discussing how Java 8 features compare to features in the Scala language—a language that, like Java, is implemented on top of the JVM and that has evolved quickly to threaten some aspects of Java’s niche in the programming language ecosystem.

Finally, chapter 21 reviews the journey of learning about Java 8 and the gentle push toward functional-style programming. In addition, we speculate on what future enhancements and great new features may be in Java’s pipeline beyond Java 8 and Java 9.