Part 4. Everyday Java

The fourth part of this book explores various new features in Java 8 and Java 9 centered around making it easier and more reliable to code your projects. We start with two APIs introduced in Java 8.

Chapter 11 covers the java.util.Optional class, which allows you to both design better APIs and reduce null pointer exceptions.

Chapter 12 explores the Date and Time API, which greatly improves the previous error-prone APIs for working with dates and time.

Then we explain Java 8 and Java 9 enhancements for writing big systems and enabling them to evolve.

In chapter 13, you’ll learn what default methods are, how you can use them to evolve APIs in a compatible way, some practical usage patterns, and rules for using default methods effectively.

Chapter 14 is new for this second edition and explores the Java Module System—a major enhancement in Java 9 that enables huge systems to be modularized in a documented and enforceable way, rather than being “only a haphazard collection of packages.”