Cannot inline bytecode built with JVM target 1.8 into bytecode that is being built with JVM target 1.6

Question

When trying to run the Example CorDapp (GitHub CorDapp) via IntelliJ, I receive the following error:

Cannot inline bytecode built with JVM target 1.8 into bytecode that is being built with JVM target 1.6

How can I modify the IntelliJ settings so that all the bytecode is built with the same JVM target?

I was able to resolve this issue by adding this library to `build.gradle` dependencies { compile("org.jetbrains.kotlin:kotlin-stdlib-jdk8") } — Munish Chandel, Oct 30 '18 at 15:44
@MunishChandel That is not sufficient. We must also do what the answer below suggests... — IgorGanapolsky, Sep 06 '19 at 14:17
Had the same error when specifying jvmTarget = "15" on Linux but the same project was working on Windows, both on IntelliJ 2020.3. Changed to jvmTarget = "14" and it worked on both. In either case there were no errors from the command line, only in IntelliJ. — AlexO, Dec 02 '20 at 21:07

Braian Coronel · Answer 1 · 2020-02-17T13:38:15.977

1483

app/build.gradle

android {
    ...
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_1_8.toString()
    }
}

GL

Use Java 8 language features

edited Feb 17 '20 at 13:38

answered Jul 11 '19 at 19:21

Braian Coronel

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As of this date and Android Studio v3.5 this is the only solution that worked, after trying all the rest. Strangely enough setting the same value in Settings > Kotlin Compiler has no effect. – user3399299 Sep 28 '19 at 06:58
95

Just the `kotlinOptions { jvmTarget = "1.8" }` should suffice. – petter Nov 04 '19 at 11:33
@petter Some libraries need both options such as `okhttp3:logging-interceptor` to use `OkHttpClient.Builder().addInterceptor` – Braian Coronel Nov 05 '19 at 16:38
kotlinOptions { jvmTarget = "1.8" } – Rob Feb 05 '20 at 13:14
8

Then should "invalidate cache and restart" – B-GangsteR Feb 22 '20 at 17:12
1

I had already define the compileOption but not kotlinOption after define kotlinOption error gone. Its work for me. Thanks for sharing. – Hitesh Dhamshaniya Mar 17 '20 at 04:48
2

And what if this is not for android? Where do the `compileOptions` and `kotlinOptions` go? – Peter V. Mørch May 14 '20 at 10:54
@PeterV.Mørch What context are you referring to? – Braian Coronel May 14 '20 at 20:14
I'm trying to include [hoplite](https://github.com/sksamuel/hoplite) in my "normal" Kotlin gradle/JVM build. When I do that, I get the error from the OP. – Peter V. Mørch May 15 '20 at 09:27
@PeterV.Mørch What module is failing you? – Braian Coronel May 15 '20 at 12:19
1

Thanks for your attempts to help me, @CORONELBraian. I figured it out - See my [answer](https://stackoverflow.com/a/61820429/345716) – Peter V. Mørch May 15 '20 at 13:28
Why some people wrap this kotlinOptions { } inside a tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all { } ? – LeonardoSibela Jul 31 '20 at 12:59
@LeonardoSibela In Gradle is that everything is executed against a Interface Project instance. These are tasks executed in the global instance of gradle, that is, at the level of the project module. So this configuration loses sense modularization since it configures all the existing build.gradle in the project. – Braian Coronel Jul 31 '20 at 14:23
If you're trying to inline 1.8 bytecode in another Gradle module, you should also put this code in another module too (not just `app`) – Vadim Kotov Oct 06 '20 at 16:02
Of course, the scope of the gradle is for the module unless you run tasks on the global gradle instance. – Braian Coronel Oct 06 '20 at 17:06

score 282 · Accepted Answer · edited Jul 17 '19 at 01:43

282

You can fix this issue as follows:

Open the IntelliJ preferences
Go to Build, Execution, Deployment > Compiler > Kotlin Compiler BUT Other Settings > Kotlin compiler if Android Studio > 3.4
Change the Target JVM version to 1.8
Click Apply

edited Jul 17 '19 at 01:43

erluxman

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answered Feb 26 '18 at 12:41

Joel

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I have this setting fixed to 1.8 already, yet I still see this error when stepping through breakpoints. I primarily see this when hitting vault queries. Any further suggestions? It seems this target JVM bit doesn't fix it entirely. – Arsalan Khalid Mar 25 '18 at 15:59
45

On your **Project Structure**, make sure you also change the `Target platform` to **JVM 1.8** on your `Kotlin` Facet under the `General` tab. – Anyul Rivas Jul 27 '18 at 12:43
1

Would you know the instructions to do the same on eclipse? – Abhi Jan 12 '19 at 20:14
3

And after Apply restart IDE. – Pavel Shorokhov Feb 10 '19 at 15:42
8

This error can appear if there is an **unresolved dependency**! – programaths Feb 14 '19 at 08:42
8

For me the `Kotlin Compiler` settings were actually placed in `Other Settings` section. – qwertyfinger Jul 03 '19 at 13:12
13

If restarting after apply is not enough → Restart & Invalidate caches. – Bartek Lipinski Aug 04 '19 at 19:40
5

Unfortunately that doesn't work if you have multiple modules. In that case you need to add ``` kotlinOptions { jvmTarget = "1.8" } ``` for every gradle in a module – Alessandro Mautone Sep 11 '19 at 10:47
1

This answer worked for me: https://stackoverflow.com/a/57586653/5046642 – Princeps Polycap Nov 21 '19 at 20:20
You should go to Kotlin Compiler – Elias Fazel Dec 31 '19 at 03:07
kotlinOptions { jvmTarget = "1.8" } – Rob Feb 05 '20 at 13:15
I do not see `General` Tab or `Build, Execution, Deployment` on Android Studio though. – c-an Mar 21 '20 at 05:57
1

As others have said, it was already set to 1.8 in the settings. Adding `kotlinOptions { jvmTarget = "1.8" } ` in the build.gradle (Module: app) fixed it. – Damn Vegetables Apr 19 '20 at 12:42
1

Doesn't work for me. Solved my problem with `kotlinOptions` – Andrey Turkovsky Apr 28 '20 at 09:59
The above did not help me. I had to add the below to Module gradle.build file: ` tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all { sourceCompatibility = JavaVersion.VERSION_1_8 targetCompatibility = JavaVersion.VERSION_1_8 kotlinOptions { jvmTarget = '1.8' apiVersion = '1.1' languageVersion = '1.1' } } ` from here: https://stackoverflow.com/questions/44141076/compilekotlin-block-in-build-gradle-file-throws-error-could-not-find-method-com – matua Jul 22 '20 at 14:38

score 139 · Answer 3 · answered Jun 22 '18 at 16:02

139

you should configure something like as follows in build.gradle

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

answered Jun 22 '18 at 16:02

Amuthan

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Or alternatively, in the Gradle Kotlin DSL: `tasks.withType { kotlinOptions.jvmTarget = "1.8" }` – breandan Nov 27 '18 at 17:21
Any idea how to get this to work with `kotlin-android` plugin? – ZeroDivide Mar 03 '19 at 17:59
Works without much hassle. I'd recommend it – Mitch Jul 01 '19 at 21:39
I had this in build.gradle, but somehow IDEA overwrote this setting. The Answer from Saeed worked for me. – nils petersohn Jul 11 '19 at 19:22
1

Do add this in your app-level Gradle's android {} section. – Parag Kadam Oct 04 '19 at 08:07
1

I get error "A problem occurred evaluating script. > Could not get unknown property 'org' for project ':subprojectName' of type org.gradle.api.Project." – naXa Jan 10 '20 at 09:21
@Amuthan, could you please include @ Parag Kadam's remark in your answer? it's essential – Antek Jun 29 '20 at 13:23

score 110 · Answer 4 · answered Jun 15 '20 at 23:09

110

please add this code to android section inside your app/build.gradle

compileOptions {
        sourceCompatibility = JavaVersion.VERSION_1_8
        targetCompatibility = JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_1_8
    }

answered Jun 15 '20 at 23:09

D. Sergeev

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its working great can you please explain it, why we need to do this and whats its mean. – Shubham Tater Jul 04 '20 at 15:13
1

it works, when my destination fragment was not able to accept navArgs() and was complaining about inline bytecode built. My app gradle had compile options for source and target but i didnt have kotlinOptions. After i added Kotlin options and clean PRoject> Rebuild Project. worked fine. – Antroid Sep 27 '20 at 00:32
It doesn't differ from the top answer. – CoolMind Nov 06 '20 at 16:15

score 88 · Answer 5 · edited Oct 15 '19 at 04:31

88

In my case, just changingTarget JVM Version like this: File > Setting > Kotlin Compiler > Target JVM Version > 1.8 did not help. However, it does resolved compile time error. But failed at runtime.

I also had to add following in app build.gradle file to make it work.

 android {
     // Other code here...
     kotlinOptions {
        jvmTarget = "1.8"
     }
 }

edited Oct 15 '19 at 04:31

ZX9

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answered Sep 17 '19 at 07:36

Md Nehaluddin Haider

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score 63 · Answer 6 · edited Apr 29 '19 at 17:48

63

When the other solutions did not work for you (Changing JVM version on Compiler settings and adding jvmTarget into your build.gradle), because of your .iml files trying to force their configurations you can change the target platform from Project Settings.

Open File > Project Structure
Go to Facets under Project Settings
- If it is empty then click on the small + button
Click on your Kotlin module/modules
Change the Target Platform to JVM 1.8 (also it's better to check Use project settings option)

edited Apr 29 '19 at 17:48

Orposuser

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answered Nov 01 '18 at 17:45

Saeed Masoumi

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I can't find this or the 'facets' section in Android Studio... I had to edit the app.iml manually. I set `````` to `true` and it worked. However, the file keeps changing back! – Aphex Dec 05 '18 at 22:36
1

@Aphex It's actually under "File" > "Project Structure" then under "Project Settings" > "Facets", I had nothing there, so I cliked "+" > "Kotlin" > Select my project. That did it for me :) – Nicolas Guillaume Feb 04 '19 at 19:05
1

This works for me, but being forced back to 1.6 every time I add to my build.gradle.kts file. – Lou Morda Feb 13 '19 at 16:29
Is there a way to have this configured and picked up from the gradle file? IMHO this being misconfigured is a bug in intellij. – Jilles van Gurp Mar 12 '19 at 14:19

score 44 · Answer 7 · edited Mar 21 '21 at 11:09

44

In my case this code didn't work until I moved apply plugin: 'kotlin-android' from bottom to top.

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'

android {
    ...
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = "1.8"
    }
}

edited Mar 21 '21 at 11:09

Zoe

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answered Mar 06 '20 at 13:13

Ara Badalyan

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kotlinOptions { jvmTarget = "1.8" } Didi the trick for me, thx – Didi May 11 '20 at 16:34

score 33 · Answer 8 · answered Jul 25 '19 at 14:01

33

In Android Studio 4.3.2 adding through the below procedure is not working.

Open the IntelliJ preferences
Go to Build, Execution, Deployment > Compiler > Kotlin Compiler BUT Other Settings > Kotlin compiler if Android Studio > 3.4
Change the Target JVM version to 1.8
Click Apply

The reason is, Android studio is unable to add the below code in the module level Gradle file. Please add it manually.

kotlinOptions {
    jvmTarget = "1.8"
}

Just for the addon, search Target JVM version in the android studio search. It will take you directly to the option.

answered Jul 25 '19 at 14:01

Muhammad Maqsood

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only by adding manually, it worked for me. For some reason, android studio is really buggy and it does not consider changes applied unless we restart the ide by deleting all cache. – Karan Sharma Feb 20 '20 at 11:51
Tnx, your solution worked for me, although I needed to restart android studio to make it reconfigure project! – Reyhane Farshbaf Dec 10 '20 at 19:24

USMAN osman · Answer 9 · 2020-02-03T07:39:40.073

28

Feb 2020
android 3.4+
Go to File -> Settings -> Kotlin Compiler -> Target JVM Version > set to 1.8 and then make sure to do File -> Sync project with Gradle files

Or add this into build.gradle(module:app) in android block:

kotlinOptions {
           jvmTarget = "1.8"
         }

edited Feb 03 '20 at 07:39

answered Feb 03 '20 at 07:26

USMAN osman

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confirmed that you need to do File -> Sync project with Gradle files, then it works – Irfandi D. Vendy Mar 17 '20 at 09:39

score 23 · Answer 10 · answered Jun 21 '18 at 19:24

23

As it is written in the using-maven docs from the Kotlin website:

You just have to put <kotlin.compiler.jvmTarget>1.8</kotlin.compiler.jvmTarget> into the properties section of your pom.xml

answered Jun 21 '18 at 19:24

Johan Vergeer

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After trying everything, yours was the only solution that worked for me – hanzo2001 Jun 30 '20 at 17:41

Fabian Braun · Answer 11 · 2020-05-18T13:45:06.350

If you have many sourcesets/modules it can be cumbersome to configure the jvmTarget for each of them separately.

You can configure the jvmTarget for all of them at once like so:

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

This snippet can be used on top level of your gradle.build file

After modifying the gradle file Reimport All Gradle Imports. To check if it worked, open Project Structure and verify that IntelliJ correctly assigned JVM 1.8 to all Kotlin-Modules. It should look like this:

I would not recommend changing the platform directly in IntelliJ, because anyone else cloning your project for the first time is likely to face the same issue. Configuring it correctly in gradle has the advantage that IntelliJ is going to behave correctly for them right from the start.

score 20 · Answer 12 · answered Jun 05 '20 at 05:23

20

In my case, jvmTarget was already set in build.gradle file as below.

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

But my issue was still there. Finally, it gets resolved after Changing Target JVM version from 1.6 to 1.8 in Preferences > Other Settings > Kotlin Compiler > Target JVM version. see attached picture,

answered Jun 05 '20 at 05:23

Shoaib Mushtaq

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Great Help, you saved my day too, Thanks – Naeem Mushtaq Jul 30 '20 at 14:58

score 19 · Answer 13 · answered Oct 05 '20 at 14:56

This helped my project to build, add this to module build.gradle file:

compileOptions {
        sourceCompatibility 1.8
        targetCompatibility 1.8
    }
    tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
        kotlinOptions {
            jvmTarget = "1.8"
        }
    }

Vikas Sharma · Answer 14 · 2019-09-08T04:23:28.880

16

In my case, I solved this by following these two steps

1. Go to android studio preferences -> other settings -> kotlin compiler -> set Target JVM version = 1.8 
   if it doesn't work then go to the second option.

2. In your module-level build.gradle file add 
   compileOptions {
        sourceCompatibility = 1.8
        targetCompatibility = 1.8
    }
    tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
        kotlinOptions {
            jvmTarget = "1.8"
        }
    }

edited Sep 08 '19 at 04:23

answered Sep 08 '19 at 04:18

Vikas Sharma

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Hey thanks for the answer, I had to do the 2nd step, and its working. Can you explain why it is needed? – hushed_voice Sep 16 '19 at 12:06
you can find more details on this closed issue it's good to know [https://github.com/mikepenz/Android-Iconics/issues/454] – Vikas Sharma Sep 24 '19 at 17:38
That link is dead – hushed_voice Sep 25 '19 at 10:48

score 15 · Answer 15 · answered Jul 10 '19 at 08:26

15

For me the reason was this configuration in my build gradle was in some modules and in some it wasnt

android {  
...      
kotlinOptions {
        val options = this as KotlinJvmOptions
        options.jvmTarget = "1.8"
    }
...
android {

answered Jul 10 '19 at 08:26

AdrianoCelentano

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Thanks, this was the only solution that worked for me. I am using kts buiild files. – Krames Jul 11 '19 at 19:47
Thanks, this is also the solutions that worked for me. And much declarative this way. https://stackoverflow.com/a/57041765/3763032 kevin also stated this, due to the smartcast in kotlin gradle files .kts it is available directly – mochadwi Aug 22 '19 at 17:13

score 12 · Answer 16 · answered Jul 15 '19 at 14:20

12

For Gradle with Kotlin language (*.gradle.kts files), add this:

android {
    [...]
    kotlinOptions {
        this as KotlinJvmOptions
        jvmTarget = "1.8"
    }
}

answered Jul 15 '19 at 14:20

Kevin Robatel

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Why do we need to cast `this` to `KotlinJvmOptions`. Isn't the `this` receiver in the `kotlinOptions` block already `KotlinJvmOptions`? Still it doesn't work for me without the cast – 11m0 Oct 25 '19 at 21:20
1

@11m0, I think it's related to this issue: https://github.com/gradle/kotlin-dsl-samples/issues/1368 – HDW Jan 02 '20 at 14:21
When KotlinJvmOptions is not found, try using the full name "org.jetbrains.kotlin.gradle.dsl.KotlinJvmOptions". – HDW Jan 02 '20 at 14:28

score 10 · Answer 17 · answered Oct 05 '20 at 12:30

10

The next solution helped me. Add to build.gradle

 compileKotlin {
    kotlinOptions.jvmTarget = "1.8"
}

compileTestKotlin {
    kotlinOptions.jvmTarget = "1.8"
}

answered Oct 05 '20 at 12:30

Олег Сухих

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Useful if you are using this without android – gbixahue Apr 28 '21 at 17:17

score 8 · Answer 18 · answered Jan 10 '20 at 09:26

8

in most cases this is enough:

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

if you have declared custom Gradle tasks like integrationTest for example, add a configuration for compile<YourTaskName>Kotlin as well:

compileIntegrationTestKotlin {
    kotlinOptions.jvmTarget = "1.8"
}

answered Jan 10 '20 at 09:26

naXa

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this would work too by adding to gradle file --> compileOptions { sourceCompatibility = 1.8 targetCompatibility = 1.8 } kotlinOptions { jvmTarget = "1.8" } – Sanket Patel Jan 18 '20 at 05:25
interestingly, only your solution worked with my non-android module! thanks! – momt99 Apr 12 '20 at 16:31

score 7 · Answer 19 · answered Feb 16 '20 at 07:18

Setting sourceCompatibility = JavaVersion.VERSION_1_8 enables desugaring, but it is currently unable to desugar all the Java 8 features that the Kotlin compiler uses.

Fix - Setting kotlinOptions.jvmTarget to JavaVersion.VERSION_1_8 in the app module Gradle would fix the issue.

Use Java 8 language features: https://developer.android.com/studio/write/java8-support

android {
  ...
  // Configure only for each module that uses Java 8
  // language features (either in its source code or
  // through dependencies).
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
  // For Kotlin projects
  kotlinOptions {
    jvmTarget = "1.8"
  }
}

score 6 · Answer 20 · answered Jan 29 '20 at 07:04

All answers here are using gradle but if someone like me ends up here and needs answer for maven:

    <build>
        <sourceDirectory>src/main/kotlin</sourceDirectory>
        <testSourceDirectory>src/test/kotlin</testSourceDirectory>

        <plugins>
            <plugin>
                <groupId>org.jetbrains.kotlin</groupId>
                <artifactId>kotlin-maven-plugin</artifactId>
                <version>${kotlin.version}</version>
                <executions>
                    <execution>
                        <id>compile</id>
                        <phase>compile</phase>
                        <goals>
                            <goal>compile</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>test-compile</id>
                        <phase>test-compile</phase>
                        <goals>
                            <goal>test-compile</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <jvmTarget>11</jvmTarget>
                </configuration>
            </plugin>
        </plugins>
    </build>

The change from jetbrains archetype for kotlin-jvm is the <configuration></configuration> specifying the jvmTarget. In my case 11

score 6 · Answer 21 · answered May 22 '20 at 15:23

if you are in android project

in your app's build.gradle under android{}

android{
//other configs...
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = "1.8"
    }
}

score 6 · Answer 22 · answered Jul 16 '20 at 06:43

You may need to set both compileKotlin and compileTestKotlin. This works on gradle 6.5.1.

compileKotlin {
    kotlinOptions {
        languageVersion = "1.2"
        apiVersion = "1.2"
        jvmTarget = "1.8"
        javaParameters = true   // Useful for reflection.
    }
}

compileTestKotlin {
    kotlinOptions {
        languageVersion = "1.2"
        apiVersion = "1.2"
        jvmTarget = "1.8"
        javaParameters = true   // Useful for reflection.
    }
}

score 4 · Answer 23 · answered Mar 08 '20 at 11:58

4

Nothing worked for me until I updated my kotlin plugin dependency.
Try this:
1. Invalidate cahce and restart.
2. Sync project (at least try to)
3. Go File -> Project Structure -> Suggestions
4. If there is an update regarding Kotlin, update it.
Hope it will help someone.

answered Mar 08 '20 at 11:58

Waldmann

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the easiest fix – u84six Mar 19 '20 at 15:29

score 4 · Answer 24 · answered May 15 '20 at 13:27

I'm using Kotlin and Gradle for normal JVM development, (not android) and this worked for me in build.gradle:

allprojects {
    tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).configureEach {
        kotlinOptions.jvmTarget = JavaVersion.VERSION_11.toString()
    }
}

score 4 · Answer 25 · answered Jun 04 '20 at 11:39

4

Using the Kotlin Gradle DSL, this solved the issue for me. I added this to the build.gradle.kts. This is in addition to the answer by Joel

val compileKotlin: KotlinCompile by tasks
compileKotlin.kotlinOptions.jvmTarget = JavaVersion.VERSION_1_8.toString()

answered Jun 04 '20 at 11:39

Briantical

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Can you please share where exactly in the file you put this? And which version of the android plugin and gradle you are using? – treesAreEverywhere Jun 04 '20 at 14:05
This is not an Android project. I am running Gradle 6.4. – Briantical Jun 09 '20 at 06:12

Amin Bahiraei · Answer 26 · 2021-04-25T09:30:50.610

4

If non of the above answers works, you can do this in kotlin dsl

android {
...

    tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile> {
        kotlinOptions {
            jvmTarget = "1.8"
        }
    }
}

edited Apr 25 '21 at 09:30

answered Dec 21 '20 at 11:05

Amin Bahiraei

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Hinotori · Answer 27 · 2019-08-22T01:49:17.420

3

If using Visual Studio Code** with Kotlin extension, go to the plugin management Crtl + Shift + x, type kotlin and click on manage (the little gear) >> Configure Extension Settings

on Kotlin >> Compiler >> Jvm:Target - type the java version. In my situation just typed 1.8

And then restart :-)

** vscode or just 'code' for linux

edited Aug 22 '19 at 01:49

answered Aug 21 '19 at 20:45

Hinotori

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score 2 · Answer 28 · answered Feb 12 '19 at 14:48

2

If you use Eclipse assuming you downloaded the Kotlin plugin:

Right click project -> Properties -> Kotlin Compiler -> Enable project specific settings -> JVM target version "1.8"

answered Feb 12 '19 at 14:48

Invest

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score 2 · Answer 29 · answered Sep 12 '19 at 18:53

2

In my case File > Setting > Kotlin Compiler > Target JVM Version > 1.8

answered Sep 12 '19 at 18:53

Bills

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score 1 · Answer 30 · answered Sep 14 '19 at 03:05

For recent versions of Android Studio, if changing just the Kotlin Target VM version didn't work.

File ➞ Project Structure ➞ Modules (app): set both "Source Compatibility" and "Target Compatibility" to "1.8 (Java 8)". Press "OK" and sync project with Gradle.

score 1 · Answer 31 · answered Mar 29 '20 at 16:11

If you'r facing this message in a Spring Boot/Kotlin project, just set the property "kotlin.compiler.jvmTarget" to "1.8" in your pom.xml.

    <properties>
        <kotlin.version>1.3.70</kotlin.version>
        <kotlin.compiler.jvmTarget>1.8</kotlin.compiler.jvmTarget>
    </properties>
    ...

score 0 · Answer 32 · answered Feb 19 '20 at 09:03

Another hint for Eclipse users. After double checking the jvm target settings pointed out by other users, I still had the same problem, and that was caused by missing Kotlin Runtime Library. For eg, when creating a project with spring initializr, it is not added automatically. For adding it: right click on your project -> Build path -> Add libraries... -> User Library, and simply add org.jetbrains.kotlin.core.KOTLIN_CONTAINER

Make sure you refresh your gradle project afterwards (right click -> Gradle -> Refresh gradle project)

Cannot inline bytecode built with JVM target 1.8 into bytecode that is being built with JVM target 1.6

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app/build.gradle

Linked