Book Image

Learn Kotlin Programming - Second Edition

By : Stephen Samuel, Stefan Bocutiu
Book Image

Learn Kotlin Programming - Second Edition

By: Stephen Samuel, Stefan Bocutiu

Overview of this book

Kotlin is a general-purpose programming language used for developing cross-platform applications. Complete with a comprehensive introduction and projects covering the full set of Kotlin programming features, this book will take you through the fundamentals of Kotlin and get you up to speed in no time. Learn Kotlin Programming covers the installation, tools, and how to write basic programs in Kotlin. You'll learn how to implement object-oriented programming in Kotlin and easily reuse your program or parts of it. The book explains DSL construction, serialization, null safety aspects, and type parameterization to help you build robust apps. You'll learn how to destructure expressions and write your own. You'll then get to grips with building scalable apps by exploring advanced topics such as testing, concurrency, microservices, coroutines, and Kotlin DSL builders. Furthermore, you'll be introduced to the kotlinx.serialization framework, which is used to persist objects in JSON, Protobuf, and other formats. By the end of this book, you'll be well versed with all the new features in Kotlin and will be able to build robust applications skillfully.
Table of Contents (21 chapters)
Free Chapter
1
Section 1: Fundamental Concepts in Kotlin
5
Section 2: Practical Concepts in Kotlin
15
Section 3: Advanced Concepts in Kotlin

Inheritance

Inheritance is fundamental to object-oriented programming. It allows us to create new classes that reuse, extend, and/or modify the behavior of preexisting ones. The preexisting class is called the super (or base or parent) class, and the brand new class we are creating is called the derived class. There is a restriction on how many super classes we can inherit from; on a JVM, you can only have one base class. But you can inherit from multiple interfaces. Inheritance is transitive. If the C class is derived from the B class and the B class is derived from a given A class, then the C class is a derived class of A.

A derived class will implicitly get all the parent classes (and the parent's parent class, if that is the case) fields, properties, and methods. The importance of inheritance lies in the ability to reuse code that has already been written and, therefore...