Book Image

Kotlin Quick Start Guide

By : Marko Devcic
Book Image

Kotlin Quick Start Guide

By: Marko Devcic

Overview of this book

Kotlin is a general purpose, object-oriented language that primarily targets the JVM and Android. Intended as a better alternative to Java, its main goals are high interoperability with Java and increased developer productivity. Kotlin is still a new language and this book will help you to learn the core Kotlin features and get you ready for developing applications with Kotlin. This book covers Kotlin features in detail and explains them with practical code examples.You will learn how to set up the environment and take your frst steps with Kotlin and its syntax. We will cover the basics of the language, including functions, variables, and basic data types. With the basics covered, the next chapters show how functions are first-class citizens in Kotlin and deal with the object-oriented side of Kotlin. You will move on to more advanced features of Kotlin. You will explore Kotlin's Standard Library and learn how to work with the Collections API. The book finishes by putting Kotlin in to practice, showing how to build a desktop app. By the end of this book, you will be confident enough to use Kotlin for your next project.
Table of Contents (15 chapters)
Title Page
Copyright and Credits
Packt Upsell

Visibility modifiers

Visibility modifiers define how your declarations are accessible from other classes and packages. In Kotlin you can use the same modifiers that are found in Java, private, protected, and public.

Private visibility modifiers restrict access to the same class or a file. And public opens the access to everybody, no matter where they are trying to access a member from.

Java also has a fourth visibility modifier, package-private, which is also a default visibility modifier (if you don’t specify a visibility modifier, then package-private is implicitly applied). Package-private in Java means that declarations are visible only inside the same package. It is easy to bypass this visibility modifier. In your code, you can declare a package with the same name as the one you wish to import from and thus break the access restriction. This is one of the reasons Kotlin doesn’t have the package-private modifier. Instead, Kotlin has a similar one, internal. Internal restricts visibility...