Duplicate class in Kotlin Android

Question

I kept on getting an error that there is a duplicate error in classes. This is what I have under org.jetbrains.kotlin folder .idea/libraries

It seems like the problem is because there is two different dependencies for Kotlin, from stdlib and stdlibjdk8, but I don't know how to remove either one from my module/project dependencies. How can I do it?

Here's the full error code:

Duplicate class kotlin.collections.jdk8.CollectionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
Duplicate class kotlin.internal.jdk7.JDK7PlatformImplementations found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk7-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.0)
Duplicate class kotlin.internal.jdk8.JDK8PlatformImplementations found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
Duplicate class kotlin.io.path.ExperimentalPathApi found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk7-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.0)
Duplicate class kotlin.io.path.PathRelativizer found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk7-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.0)
Duplicate class kotlin.io.path.PathsKt found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk7-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.0)
Duplicate class kotlin.io.path.PathsKt__PathReadWriteKt found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk7-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.0)
Duplicate class kotlin.io.path.PathsKt__PathUtilsKt found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk7-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.0)
Duplicate class kotlin.jdk7.AutoCloseableKt found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk7-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.0)
Duplicate class kotlin.jvm.jdk8.JvmRepeatableKt found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
Duplicate class kotlin.random.jdk8.PlatformThreadLocalRandom found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
Duplicate class kotlin.streams.jdk8.StreamsKt found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$1 found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$2 found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$3 found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$4 found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
Duplicate class kotlin.text.jdk8.RegexExtensionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
Duplicate class kotlin.time.jdk8.DurationConversionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)

I've tried deleting the files from the org.jetbrains.kotlin, but whenever I build the app in Android Studio, the files will be redownloaded again.

This is my module app Gradle code:

plugins {
    id 'com.android.application'
    id 'com.google.gms.google-services'
}

android {
    compileSdk 33

    defaultConfig {
        applicationId "com.example.umfs"
        minSdk 21
        targetSdk 32
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    buildFeatures {
        viewBinding true
    }

    namespace 'com.example.umfs'
}

dependencies {

    implementation 'androidx.appcompat:appcompat:1.5.1'
    implementation 'com.google.android.material:material:1.7.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
    implementation 'com.google.firebase:firebase-database:20.1.0'
    implementation 'androidx.preference:preference:1.2.0'
    implementation 'com.google.firebase:firebase-auth:21.1.0'
    implementation 'com.google.firebase:firebase-core:21.1.1'
    implementation 'androidx.navigation:navigation-fragment:2.5.3'
    implementation 'androidx.navigation:navigation-ui:2.5.3'
    implementation 'com.google.firebase:firebase-firestore:24.4.1'
    implementation 'androidx.recyclerview:recyclerview:1.2.1'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.4'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.0'
    implementation 'de.hdodenhof:circleimageview:3.1.0'
    implementation "androidx.cardview:cardview:1.0.0"
    implementation 'com.google.firebase:firebase-firestore:24.4.1'
    implementation 'com.google.firebase:firebase-storage:20.1.0'
    implementation 'com.google.firebase:firebase-database'
    implementation platform('com.google.firebase:firebase-bom:28.4.0')
    implementation 'com.squareup.picasso:picasso:2.71828'
    implementation 'com.makeramen:roundedimageview:2.3.0'
    implementation 'com.github.bumptech.glide:glide:4.14.2'
    implementation 'com.github.marlonlom:timeago:4.0.3'
    implementation "androidx.core:core-ktx:+"

}

apply plugin: 'com.google.gms.google-services'

Answer 1

Simply. For me, just change this Gradle plugin from 1.7.10 to 1.8.0 Then synchronise → invalidate caches → build

From:

plugins {
    ....
    id 'org.jetbrains.kotlin.android' version '1.7.10' apply false
}

To:

plugins {
    ....
    id 'org.jetbrains.kotlin.android' version '1.8.0' apply false
}

Answer 2

See this note in the official Kotlin documentation for an explanation of how alignment works with these dependencies and build flags. The below original answer is an alternative approach which doesn't take this into account.

This is because kotlin-stdlib-jdk7 and kotlin-stdlib-jdk8 are older dependencies that should be replaced by kotlin-stdlib (As @MrPNG pointed out from the what's new docs for Kotlin 1.8). However, other libraries may still declare a dependency on them, which needs to be replaced with a dependency on kotlin-stdlib.

You can override how the jdk7 and jdk8 versions are resolved like this (in your app/build.gradle):

dependencies {
    constraints {
        implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.8.0") {
            because("kotlin-stdlib-jdk7 is now a part of kotlin-stdlib")
        }
        implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.8.0") {
            because("kotlin-stdlib-jdk8 is now a part of kotlin-stdlib")
        }
    }
}

The constraints section above can be added in alongside your other dependencies. Choose the version (here 1.8.0) to match the one you actually want to be used, which should be the one that your non-jdkN-named version is in the duplicate class error (e.g., (org.jetbrains.kotlin:kotlin-stdlib:1.8.0))

If you have apply plugin: 'kotlin-android' in this file, then it doesn't need to separately also say to depend on the stdlib in dependencies, so remove any lines that look like this:

    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"

(thanks to this blog)

Answer 3

I have tried all the previous solutions but after adding the below code it was working.

dependencies {
   ... ... ...
   implementation(platform("org.jetbrains.kotlin:kotlin-bom:1.8.0"))
   ... ... ...
}

Answer 4

I was getting the same error after upgrading the Android annotation library from version 1.4.0 to 1.6.0,

implementation 'androidx.annotation:annotation:1.6.0'

So I downgraded to 1.5.0 and the error was gone:

implementation 'androidx.annotation:annotation:1.5.0'

Answer 5

Upgrade kotlin android plugin and kotlin compiler

plugins {
    id 'org.jetbrains.kotlin.android' version '1.8.10'
}
android {
    composeOptions {
        kotlinCompilerExtensionVersion = "1.4.3"
    }
}

Answer 6

You can now update the lifecycle dependencies to the most up-to-date versions, and simply add the following line in your build.gradle

dependencies {

    (...)

    // Fix Duplicate class
    implementation(platform("org.jetbrains.kotlin:kotlin-bom:1.8.0"))

}

Answer 7

I tried many ways to solve this same prolem but didnt work I tried to add this dependencies below in my "build.gradle(module:app)"..

implementation (platform("org.jetbrains.kotlin:kotlin-bom:1.8.0"))

and then synce now, it will resolve this error.

Answer 8

I solved the problem by changing the Kotlin class path dependency in the root build.gradle file from

classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.7.20-RC"

to

classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.8.0"

Answer 9

edit app/build.gradle file in flutter

dependencies {

    (...)

    // Fix Duplicate class
    implementation(platform("org.jetbrains.kotlin:kotlin-bom:1.8.0"))

}

Answer 10

Add the below line in your build.gradle(Module:app)

dependencies {

(...)

// Fix Duplicate class
implementation(platform("org.jetbrains.kotlin:kotlin-bom:1.8.0"))

}

This is because kotlin-stdlib-jdk7 and kotlin-stdlib-jdk8 are older dependencies that should be replaced by kotlin-stdlib. However, other libraries may still declare a dependency on them, which needs to be replaced with a dependency on kotlin-stdlib.

Answer 11

This problem will be solved by adding the dependency in build.gradle(app) file

implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.8.0"

it's working properly

Answer 12

I was using org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10 before in our SDK and then I updated kotlin to v1.8.0 and that's when I started getting the above error in our Android Java front end application. Using org.jetbrains.kotlin:kotlin-bom resolved the issue with transitive dependencies and might be a cleaner approach since it doesn't leak Kotlin details into the Java application.

so I just replaced

implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10"

with below which solved the problem for me.

// Align versions of all Kotlin components
implementation(platform("org.jetbrains.kotlin:kotlin-bom:1.8.0"))
implementation "org.jetbrains.kotlin:kotlin-stdlib:1.8.0"

Answer 13

You will get this type of Duplicate Kotlin Class Issue

Fix for This Issue:

android/app/build.gradle--->

dependencies {

    implementation(platform("org.jetbrains.kotlin:kotlin-bom:1.8.0"))

}

Add this dependency and it will fix the issue immediately.

Answer 14

If you are using Compose you need to update the Compose Compiler (https://developer.android.com/jetpack/androidx/releases/compose-compiler) to 1.4.2 and Kotlin to 1.8.10 at the same time.

Answer 15

Use:

configurations.all {
    resolutionStrategy {
        force 'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.8.10'
    }
}

Adding this to the end of the Gradle file helps.

Answer 16

Step 1: Add this

plugins {
        id 'com.android.application'
        id 'org.jetbrains.kotlin.android' version '1.8.10' apply false
    }

Step 2: Add this on the dependencies

dependencies {

.....

  constraints{
        implementation 'org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.8.10'
        implementation 'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.8.10'
    }
}

Note: version '1.8.10', jdk7:1.8.10 and jdk8:1.8.10 are the same...

Answer 17

Go to the settings.gradle, change the following line:-

From :

plugins {
....
id 'org.jetbrains.kotlin.android' version '1.7.10' apply false 

}

To :

plugins {
....
id 'org.jetbrains.kotlin.android' version '1.8.0' apply false

}

Then run your app.

Answer 18

I had the same error on my Kotlin project. When I add Ktor to my project and upgraded the library versions, and then I got the wired long error. This is how I fixed it.

I used compose version 1.4.0

ext {
    compose_ui_version = '1.4.0'
}

kotlin version 1.8.0, the latest one 1.8.10 not compatible with compose 1.4.0 So I used,

id 'org.jetbrains.kotlin.android' version '1.8.0' apply false

Then, adjust the composeOptions on app level build.gradle file, like

composeOptions {
    kotlinCompilerExtensionVersion '1.4.0'
}

These are the three changes that I have done and I got escaped from the wired error. Hope this will help someone.

Answer 19

lifecycle-viewmodel-ktx-2.6.1

down

lifecycle-viewmodel-ktx-2.5.1

I managed to get it working by lowering the dependency values.

Answer 20

I fixed it by making Compose Compiler and JetBrains Kotlin plugins compatible

First, make sure are you using org.jetbrains.kotlin.android plugin version above 1.8.0.

build.gradle(Project)

plugins {
  ...
  id 'org.jetbrains.kotlin.android' version '1.8.21' apply false
}

Then check compatible version of Compose Compiler from below link and update build.gradle(app):
https://developer.android.com/jetpack/androidx/releases/compose-kotlin#pre-release_kotlin_compatibility

android {
  ...
  composeOptions {
    kotlinCompilerExtensionVersion '1.4.7'
  }
}

Answer 21

add this inside your dependencies, it will solve the error.

dependencies {

    (...)

    // Fix Duplicate class
    implementation(platform("org.jetbrains.kotlin:kotlin-bom:1.8.0"))

}

Answer 22

Workaround for earlier KGP versions now is:

File app/build.gradle

dependencies {
    constraints {
        implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.8.0") {
            because("kotlin-stdlib-jdk7 is now a part of kotlin-stdlib")
        }
        implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.8.0") {
            because("kotlin-stdlib-jdk8 is now a part of kotlin-stdlib")
        }
    }
}

Answer 23

According to the release notes of Kotlin 1.8.0 (https://kotlinlang.org/docs/whatsnew18.html#updated-jvm-compilation-target), you shouldn't specify kotlin-stdlib-jdk7 nor kotlin-stdlib-jdk8 as dependencies anymore and, instead, just use kotlin-stdlib.

Answer 24

I ran into this issue today and I fixed it by upgrading both Kotlin std-lib for android and the std-lib itself. Also it's worth mentioning that if you're using compose, you have upgrade the kotlinCompilerExtensionVersion

Here is the final setup

• gradle file at Module level

composeOptions {
    kotlinCompilerExtensionVersion '1.4.3'
}

• root project gradle file

plugins {
    id 'com.android.application' version '7.3.1' apply false
    id 'com.android.library' version '7.3.1' apply false
    id 'org.jetbrains.kotlin.android' version '1.8.10' apply false
    id 'org.jetbrains.kotlin.jvm' version '1.8.10' apply false
}

Answer 25

This happened to me when upgrading one of these

implementation 'androidx.navigation:navigation-fragment:2.5.3'
implementation 'androidx.navigation:navigation-ui:2.5.3'

To version 2.6.0. When rolling back to 2.5.3 the error went away.

Answer 26

If I update kotlin version to 1.8.0 then it forces me to use view binding

i.e. classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.8.10'

then if you want to keep kotlin version as it was before then just add it in app level gradle-

implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.8.0"

it will solve duplicate class issues though it is a temporary solution. Here my AGP version is 7.4.1 and Gradle version is 7.5

Answer 27

The issue may be easely fixed by one line only:

dependencies {
.....
    implementation 'org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.9.0'
}

Answer 28

It is maybe some updated version dependency. In my new compose app, when I updated

implementation 'androidx.compose.material3:material3:*'(new version) from 1.0.0-alpha11

I will got this error. Try revert updated dependency.

Also, I was getting this error when android studio was added in my Gradle modules ktx:+ dependency.

Answer 29

I had the same errors in my project. What finally helped me was the following steps

1-I have updated the buildScript: as below

buildscript {
    ext {
        compose_ui_version = '1.3.3'
    }
}
then change pluggin 
From

plugins {
....
id 'org.jetbrains.kotlin.android' version '1.7.10' apply false

}

To

plugins {
....
id 'org.jetbrains.kotlin.android' version '1.8.10' apply false
}

lastly updated in build.grade(app)

Change in android scope {}

    android {
    ......
    composeOptions {
            kotlinCompilerExtensionVersion '1.2.0'
        }
    .......
    }

To the following and the errors were gone

 composeOptions {
        kotlinCompilerExtensionVersion = "1.4.3"
    }

Hope it helps someone else 

Answer 30

kotlinCompilerExtensionVersion(compose) -> kotlin_version

1.4.4 -> 1.8.10

1.4.3 -> 1.8.10

1.4.2 -> 1.8.10

1.4.1 -> 1.8.0

1.4.0 -> 1.8.0

1.4.0-alpha02 -> 1.7.21

1.4.0-alpha01 -> 1.7.20

1.3.2 ->1.7.20

...

Other versions: https://developer.android.com/jetpack/androidx/releases/compose-kotlin