Chapter 4. Classes, objects, and interfaces
This chapter covers
- Classes and interfaces
- Nontrivial properties and constructors
- Data classes
- Class delegation
- Using the object keyword
This chapter gives you a deeper understanding of working with classes in Kotlin. In chapter 2, you saw the basic syntax for declaring a class. You know how to declare methods and properties, use simple primary constructors (aren’t they nice?), and work with enums. But there’s more to see.
Kotlin’s classes and interfaces differ a bit from their Java counterparts: for example, interfaces can contain property declarations. Unlike in Java, Kotlin’s declarations are final and public by default. In addition, nested classes aren’t inner by default: they don’t contain ...