Kotlin Help

Get started with Gradle and Kotlin/JVM

This tutorial demonstrates how to use IntelliJ IDEA and Gradle to create a JVM console application.

To get started, first download and install the latest version of IntelliJ IDEA.

Create a project

  1. In IntelliJ IDEA, select File | New | Project.

  2. In the panel on the left, select Kotlin.

  3. Name the new project and change its location, if necessary.

    Create a console application
  4. Select the Gradle build system.

  5. From the JDK list, select the JDK that you want to use in your project.

    • If the JDK is installed on your computer, but not defined in the IDE, select Add JDK and specify the path to the JDK home directory.

    • If you don't have the necessary JDK on your computer, select Download JDK.

  6. Select the Kotlin DSL for Gradle.

  7. Select the Add sample code checkbox to create a file with a sample "Hello World!" application.

  8. Click Create.

You have successfully created a project with Gradle!

Specify a Gradle version for your project

You can explicitly specify a Gradle version for your project under the Advanced Settings section, either by using the Gradle Wrapper or a local installation of Gradle:

  • Gradle Wrapper:

    1. From the Gradle distribution list, select Wrapper.

    2. Disable the Auto-select checkbox.

    3. From the Gradle version list, select your Gradle version.

  • Local installation:

    1. From the Gradle distribution list, select Local installation.

    2. For Gradle location, specify the path of your local Gradle version.

    Advanced settings

Explore the build script

Open the build.gradle.kts file. This is the Gradle Kotlin build script, which contains Kotlin-related artifacts and other parts required for the application:

plugins { kotlin("jvm") version "2.0.0" // Kotlin version to use } group = "org.example" // A company name, for example, `org.jetbrains` version = "1.0-SNAPSHOT" // Version to assign to the built artifact repositories { // Sources of dependencies. See 1️⃣ mavenCentral() // Maven Central Repository. See 2️⃣ } dependencies { // All the libraries you want to use. See 3️⃣ // Copy dependencies' names after you find them in a repository testImplementation(kotlin("test")) // The Kotlin test library } tasks.test { // See 4️⃣ useJUnitPlatform() // JUnitPlatform for tests. See 5️⃣ }

As you can see, there are a few Kotlin-specific artifacts added to the Gradle build file:

  1. In the plugins {} block, there is the kotlin("jvm") artifact. This plugin defines the version of Kotlin to be used in the project.

  2. In the dependencies {} block, there is testImplementation(kotlin("test")). Learn more about setting dependencies on test libraries.

Run the application

  1. Open the Gradle window by selecting View | Tool Windows | Gradle:

    Main.kt with main fun
  2. Execute the build Gradle task in Tasks\build\. In the Build window, BUILD SUCCESSFUL appears. It means that Gradle built the application successfully.

  3. In src/main/kotlin, open the Main.kt file:

    • src directory contains Kotlin source files and resources.

    • Main.kt file contains sample code that will print Hello World!.

  4. Run the application by clicking the green Run icon in the gutter and select Run 'MainKt'.

    Running a console app

You can see the result in the Run tool window:

Kotlin run output

Congratulations! You have just run your first Kotlin application.

What's next?

Learn more about:

Last modified: 01 May 2024