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


With exception handling features of a language, you can deal with unpredicted situations or exceptional states that can occur while your code is executing. Kotlin is no different from other languages, like C# and Java and has the same keywords for handling exceptions. These are try, catch, and finally. With these keywords, you can execute a function or some other action which may fail, execute some code in case of failure, and do a cleanup of resources.

val file = File("foo")
var stream: OutputStream? = null
try {
    stream = file.outputStream()
//do something with stream
} catch (ex: FileNotFoundException) {
println("File doesn't exist")
} finally {
if (stream != null) stream.close()

When you detect an error, or an exceptional state has occurred, you can tell that to the runtime by raising an exception. The caller of your function can catch that exception and try to recover it from an exceptional state. If he doesn’t, then the exception is thrown further up the function call...