How do I set the jvm target for android studio using gradle and kotlin?

Question

I get the following error when trying to compile a unit test written in kotlin.

Task :app:compileDebugUnitTestKotlin FAILED ...Cannot inline bytecode built with JVM target 1.7 into bytecode that is being built with JVM target 1.6. Please specify proper '-jvm-target' option

I've tried setting the source compatibility for my android configuration in my app build.gradle:

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

as well as configuring all kotlin compile tasks in the root build.gradle:

tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
    kotlinOptions {
        jvmTarget = '1.8'
    }
}

@ZeroDivide can you please mark as correct answer this https://stackoverflow.com/a/58094987/5040556 — Daniele, Jun 08 '20 at 10:55

score 40 · Answer 1 · edited Apr 12 '20 at 23:01

40

This is a temporary Android Studio bug. I needed to add these lines to the app's gradle file:

android {
    ...
    compileOptions {
        sourceCompatibility = 1.8
        targetCompatibility = 1.8
    }
    kotlinOptions {
        jvmTarget = "1.8"
    }
    ...
}

edited Apr 12 '20 at 23:01

aschepler

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answered Sep 25 '19 at 09:11

Daniele

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7

Looks like this "temporary" bug is still there nine months later. – Oscar Jul 05 '20 at 23:45
1

I only needed to add the kotlinOptions portion to work around it in my project. – Oscar Jul 06 '20 at 00:20

score 11 · Answer 2 · answered Mar 05 '19 at 03:47

11

1)On a Mac

Android Studio -> Preferences -> Kotlin Compiler -> Change Target JVM version

2) PC

Android Studio -> File -> Settings -> Kotlin Compiler -> Change Target JVM version

answered Mar 05 '19 at 03:47

rafa

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That is set to `1.8`, and shouldn't affect the `gradle` build. – Stephen__T Mar 05 '19 at 16:45
Why wouldn't it affect the Gradle build? What is its purpose then? Also... I tried this setting and it had no effect on this error. I can't find where 1.6 is being specified. – Oscar Jul 06 '20 at 00:17
This is a good suggestion but it's not woking on Android Studio 4.0.1. The alert continuos showing as red code. When I specify in build.gradle(app) finally stop showing those red code suggestions. – Hanako Jun 27 '21 at 01:03
1

I am not a person. – Dávid Horváth Sep 07 '22 at 12:23

score 3 · Answer 3 · answered Sep 28 '20 at 12:08

3

The default target JVM bytecode is 1.6. But this can be set by changing build.gradle(:app):

android{
...
    kotlinOptions {
        jvmTarget = 1.8
    }
}

It seems, the Android Studio Kotlin compiler target JVM option does not work.

answered Sep 28 '20 at 12:08

CodingFrog

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score 1 · Answer 4 · answered Aug 16 '22 at 12:12

1

you need to add this in build.gradle file.

android {
  kotlinOptions {
    jvmTarget = "1.8"
    freeCompilerArgs += [
        '-Xjvm-default=enable'
    ]
  }

}

answered Aug 16 '22 at 12:12

Ahmad Bhatti

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How do I set the jvm target for android studio using gradle and kotlin?

4 Answers4