Intellij refuses to set the Kotlin target jvm to 1.8?

Question

ParallelStreams.kts:41:15: error: calls to static methods in Java interfaces are prohibited in JVM target 1.6. Recompile with '-jvm-target 1.8'
IntStream.range(0,10).parallel().forEach{a ->
         ^

Ok ... I'm not trying to compile for 1.6.

File > Project Structure > Project has project sdk 1.8 and language level 8.

File > Project Structure > Modules > Kotlin has target platform: JVM 1.8.

File > Project Structure > Facets > Kotlin has target platform: JVM 1.8.

File > Settings > Compiler > Kotlin Compiler has target jvm version 1.8.

My gradle build file ...

plugins {
    id 'org.jetbrains.kotlin.jvm' version '1.3.0'
}

group 'foo'
version '1.0-SNAPSHOT'

repositories {
    mavenCentral()
}

dependencies {
    //kotlin
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
    implementation "org.jetbrains.kotlin:kotlin-script-runtime:1.3.0"

    //networking
    implementation 'com.mashape.unirest:unirest-java:1.4.9'
}

compileKotlin {
    kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
    kotlinOptions.jvmTarget = "1.8"
}

I'm running out of places to check for 1.8.

And yes, I have tried invalidating the cache and restarting Intellij. It does nothing to resolve this issue.

I had the same problem that I couldn't find the right setting in IntelliJ IDEA to change the target JVM version for Kotlin scripts using pure IDEA project file structure (not Gradle). It seems that it's 1.6 by default and can't be changed by now. However, If you just want the scripts to run normally, you can bring down all such settings to 6 or 1.6, since the bytecode version doesn't actually affect the program logic or what Kotlin APIs you use. This works for me. — Shreck Ye, Sep 28 '19 at 16:50

score 6 · Answer 1 · answered Feb 11 '19 at 22:11

6

Add sourceCompatibility and targetCompatibility for Java 1.8:

plugins {
  id 'org.jetbrains.kotlin.jvm' version '1.3.0'
}

group 'foo'
version '1.0-SNAPSHOT'

repositories {
  mavenCentral()
}

// Add compatibility
sourceCompatibility = JavaVersion.VERSION_1_8
targetCompatibility = JavaVersion.VERSION_1_8


dependencies {
  //kotlin
  implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
  implementation "org.jetbrains.kotlin:kotlin-script-runtime:1.3.0"

  //networking
  implementation 'com.mashape.unirest:unirest-java:1.4.9'
}

compileKotlin {
  kotlinOptions.jvmTarget = "1.8"
}
compileTestKotlin {
  kotlinOptions.jvmTarget = "1.8"
}

answered Feb 11 '19 at 22:11

punchman

1,350
1
13
23

1

Afraid that doesn't change anything. – User1291 Feb 11 '19 at 22:15
Did you try this answer https://stackoverflow.com/a/48607469/9060113? (also see to comments) – punchman Feb 11 '19 at 22:21
Yes ...tried everything I mentioned in the post above. – User1291 Feb 11 '19 at 22:22

score 4 · Answer 2 · edited May 09 '19 at 09:15

4

With .kts just use this:

tasks {
    withType<KotlinCompile> {
        kotlinOptions.jvmTarget = "1.8"
    }
}

// I am using latest dsl and gradle 
val kotlinVersion = "1.3.30"
val gradleVersion = "5.4+"

edited May 09 '19 at 09:15

Hasta Dhana

4,699
7
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answered May 09 '19 at 09:01

Golvanig

41
2

1

Don't forget to `import org.jetbrains.kotlin.gradle.tasks.KotlinCompile` – O.Badr Aug 13 '20 at 23:20

score 1 · Answer 3 · answered Feb 11 '19 at 23:21

1

Since compilation tasks are generated for all relevant configurations it is likely that just changing compileKotlin and compileTestKotlin isn't enough.

Try using task filtering to configure all KotlinCompile task instances:

tasks.withType(KotlinCompile) {
    kotlinOptions.jvmTarget = "1.8"
}

answered Feb 11 '19 at 23:21

Kiskae

24,655
2
77
74

Did try ... no change. :( Thanks, though. – User1291 Feb 12 '19 at 06:29

Intellij refuses to set the Kotlin target jvm to 1.8?

3 Answers3

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