Chapter 1. Kotlin: what and why


This chapter covers

  • A basic demonstration of Kotlin
  • The main traits of the Kotlin language
  • Possibilities for Android and server-side development
  • What distinguishes Kotlin from other languages
  • Writing and running code in Kotlin

What is Kotlin all about? It’s a new programming language targeting the Java platform. Kotlin is concise, safe, pragmatic, and focused on interoperability with Java code. It can be used almost everywhere Java is used today: for server-side development, Android apps, and much more. Kotlin works great with all existing Java libraries and frameworks and runs with the same level of performance as Java. In this chapter, we’ll explore Kotlin’s main traits in detail.

1.1. A taste of Kotlin

Let’s start with a small example to demonstrate what Kotlin looks like. This example defines a Person class, creates a collection of people, finds the oldest one, and prints the result. Even in this small piece of code, you can see many interesting features of Kotlin; we’ve highlighted some of them so you can easily find them later in the book. The code is explained briefly, but please don’t worry if something isn’t clear right away. We’ll discuss everything in detail later.

If you’d like to try running this example, the easiest option is to use the online playground at Type in the example and click the Run button, and the code will be executed.

1.2. Kotlin’s primary traits

1.3. Kotlin applications

1.4. The philosophy of Kotlin

1.5. Using the Kotlin tools

1.6. Summary