Kotlin is a statically typed programming language that targets the JVM, Android, JavaScript, and Native. It is developed by JetBrains. Kotlin is designed to interoperate fully with Java, and the JVM version can run any Java code. Kotlin is released under the Apache 2 open source license.
According to JetBrains, over 60% of Kotlin projects use the language for backend development. The reasons for this are numerous: Kotlin is concise, safe, Null-Pointer-Proof™, and has great tooling support. It is also 100% interoperable with Java, meaning that you can use all existing Java libraries in your Kotlin code.
In this article, we'll take a look at how to get started with Kotlin for backend development. We'll see how to set up a Kotlin project, write code in Kotlin, and run it on the JVM.
There are many ways to set up a Kotlin project. In this article, we'll use the Gradle build tool. Gradle is a build tool with a focus on build automation and support for multiple languages. Kotlin projects can be easily created using the Gradle Kotlin DSL.
The first thing we need to do is create a file called build.gradle.kts in the root of our project. This file contains the configuration for our Kotlin project.
plugins {
id("org.jetbrains.kotlin.jvm") version "1.3.72"
}
group = "com.example"
version = "1.0-SNAPSHOT"
repositories {
jcenter()
}
dependencies {
implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
}
tasks.withType<Test> {
useJUnitPlatform()
}
In the build.gradle.kts file, we've configured the Kotlin plugin and added a dependency on the Kotlin stdlib. We've also configured the test task to use the JUnit platform.
Now that we have a Kotlin project set up, we can write some Kotlin code. We'll start by creating a file called Main.kt in the src/ directory.
In Main.kt, we'll write a simple Kotlin program that prints "Hello, world!" to the console.
fun main() {
println("Hello, world!")
}
Kotlin programs start with a main function. The main function is the entry point for our program. In the main function, we've printed the string "Hello, world!" to the console.
Kotlin code can be run on the JVM without any additional configuration. To run our Kotlin program, we can use the gradle run command. This will compile our Kotlin code and run the main function.
$ gradle run
> Task :run
Hello, world!
BUILD SUCCESSFUL in 0s
2 actionable tasks: 2 executed
In this article, we've seen how to get started with Kotlin for backend development. We've set up a Kotlin project, written some Kotlin code, and run it on the JVM. Kotlin is a great language for backend development, and we've only scratched the surface of what it can do.