Getting Started with Kotlin

It is time to write code. In this chapter, we will go over and write the typical entry code example for every language—the famous Hello World!. In order to do this, we will need to set up the initial environment required to develop software with Kotlin. We will provide a few examples using the compiler from the command line, and then we will look at the typical way of programming using the integrated development environments (IDEs) and build tools available.

Kotlin is a Java virtual machine (JVM) language, and so the compiler will emit Java bytecode. Because of this, naturally, Kotlin code can call Java code, and vice versa! Therefore, you need to have the Java Development Kit (JDK) installed on your machine. To be able to write code for Android, where the most recent supported Java version is 6, the compiler needs to translate your code to bytecode that is at least compatible with Java 6. 

In this chapter, you will learn how to do the following:

• Use the command line to compile and execute code written in Kotlin
• Use the REPL and write Kotlin scripts
• Create a Gradle project with Kotlin enabled
• Create a Maven project with Kotlin enabled
• Use IntelliJ to create a Kotlin project
• Use Eclipse IDE to create a Kotlin project
• Mix Kotlin and Java code in the same project