Chapter 1, The Power of Kotlin, is the introductory chapter. It covers why Kotlin is quickly becoming a force to reckon with. Kotlin positions itself as the smart choice to the various stakeholders, such as the programmer, the manager, and the businesses. The chapter looks at the technology and business reasons that fuel the adoption of Kotlin. 

Chapter 2, Geospatial Messenger – Spring Boot, covers the use of Spring Boot technology to create robust server-side applications. Spring is one of the most well-known and well-respected server-side frameworks in the Java space, and Spring Boot is its less verbose and more powerful version. This chapter covers how a Geospatial Messenger application is created with Spring Boot technology using the Kotlin language.

Chapter 3, Social Media Aggregator Android App, is using Kotlin to create native Android apps. With Google officially recognizing Kotlin's use to develop Android apps, this is the most widespread application to use the Kotlin language. Today's mobile apps hardly work in isolation. They work with a server. This common scenario is illustrated with a social media aggregator app.

Chapter 4, Weather App Using Kotlin for JavaScript, explores the use of Kotlin to create rich internet apps that work within the browser. JavaScript is clearly the de facto standard language that works across all the browsers. However, Kotlin is clearly superior to JavaScript in many ways. This chapter shows how one can have the best of both worlds by doing the coding in Kotlin and, then, transpiling the code to JavaScript so that it works with the browsers seamlessly. The example that we will build is a simple weather application.

Chapter 5, Chat Application with Server-Side JavaScript Generation, explores how the same facility of transpiling Kotlin to Javascript can be used on the server side. JavaScript is used on the server side within the popular and fast Node.js framework. Kotlin can be used to create Node.js applications, as the JavaScript code that runs with Node.js can be generated from it. This chapter shows how to do so by creating a simple chat application.

Chapter 6, News Feed – REST API, covers the use of Kotlin specifically to create REST services. We will develop a News Feed application with the Ktor framework, which is a leading Kotlin-only framework used for server-side applications.

Chapter 7, CSV Reader in Kotlin Native, explores a bleeding edge technology—Kotlin Native—which is about compiling Kotlin code directly to platform-specific executables. Although not mature, Kotlin Native is worth watching as it quickly marches to its promise of becoming the only language to create native applications across disparate platforms such as iOS and Raspberry Pi. In this chapter, a small CSV reader utility is built with Kotlin/Native.

Chapter 8, Dictionary Desktop Application - Tornado FX, is about using Kotlin to create a cross-platform desktop application based on Java technology. Tornado FX is a Kotlin-specific framework, which is based on the most advanced Java GUI framework, that is, Java FX. This chapter illustrates the power of Tornado FX with a dictionary application.

You will need to have the following:

This practical guide is for programmers who are already familiar with Kotlin. If you are familiar with Kotlin and want to put your knowledge to work, then this is the book for you. Kotlin programming knowledge is a must.

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in the text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: " We will break the Result object returned from the function and catch it inside two objects named result and status."

A block of code is set as follows:

    var createTweet: Button? = null
    createTweet.setOnClickListener({
      // Do button click operation
    })

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

    fun ViewGroup?.inflate(layoutId: Int, attachToRoot: Boolean) =  
     LayoutInflater.from(this?.context).inflate(layoutId, this, 
     attachToRoot)

Any command-line input or output is written as follows:

npm init

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Create a new project in IntelliJ, select Gradle and add the dependencies related to Spring Boot and Kotlin."

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