Kotlin Multiplatform pass (JVM) arguments to the app using Gradle

Question

I'm trying to pass arguments to my Kotlin Multiplatform desktop app.

I have this in my build.gradle.kts:

tasks.withType<JavaExec> { args = listOf("test") }

This is my Main.kt file:

fun main(args: Array<String>) { println(args.toList()) // ... }

When I run my app using ./gradlew run, this is printed:

[]

The run task is of type JavaExec, why are the arguments not being passed then?

I also tried jvmArgs:

tasks.withType<JavaExec> { jvmArgs = listOf("-Dtest=true") }

and this in my Main.kt:

fun main(args: Array<String>) { println(System.getProperty("test")) // ... }

But again, when running ./gradlew run, the output is:

null

UPDATE

I tried using specific name as suggested in the comments:

tasks.named<JavaExec>("run") { args = listOf("test") jvmArgs = listOf("-Dtest=true") }

but I know get an error:

Task with name 'run' not found in project ':composeApp'.

I also tried this:

tasks.withType<JavaExec> { println("Exec TASK: $name, $args, $jvmArgs") args = listOf("test") jvmArgs = listOf("-Dtest=true") }

and this is the output:

Exec TASK: run, [], [] Exec TASK: runRelease, [], [] Exec TASK: desktopRun, [], []

So using tasks.withType<JavaExec> does find some tasks, but for some reason still doesn't set their arguments.

Instead of using tasks.withType<JavaExec>, target the exact run task created by the application plugin: application { mainClass.set("your.package.MainKt") } tasks.named<JavaExec>("run") { args = listOf("test") jvmArgs = listOf("-Dtest=true") } — Vijay
– Vijay, Commented Apr 12 at 1:22

Mahozad · Accepted Answer · 2025-06-11 11:36:45Z

As said in the official docs, simply add your app arugments in your build.gradle.kts file like this:

compose.desktop { application { // ... args += listOf( "hello", "my second arg" ) } }

You can also set VM arguments used by the JVM to execute your app using jvmArgs property:

jvmArgs += "--add-opens=java.base/java.nio=ALL-UNNAMED"

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