Duplicate class in Kotlin Android

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
}

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)

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"))
   ... ... ...
}

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'

Upgrade kotlin android plugin and kotlin compiler

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

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"))

}

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.

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"

edit app/build.gradle file in flutter

dependencies {

    (...)

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

}

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.

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

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"

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.

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.

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...

Use:

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

Adding this to the end of the Gradle file helps.

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.

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.

lifecycle-viewmodel-ktx-2.6.1

down

lifecycle-viewmodel-ktx-2.5.1

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

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'
  }
}

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

dependencies {

    (...)

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

}

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")
        }
    }
}

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.

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
}

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.

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

The issue may be easely fixed by one line only:

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

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.

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 

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