Question 234957 in Flutter Question posted in
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Duplicate class error in flutter when starting app

When I want to start my app, I get this error message:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:checkDebugDuplicateClasses'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.CheckDuplicatesRunnable
   > Duplicate class kotlin.collections.jdk8.CollectionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
     Duplicate class kotlin.internal.jdk8.JDK8PlatformImplementations found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
     Duplicate class kotlin.jvm.jdk8.JvmRepeatableKt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) 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-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) 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-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$1 found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$2 found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$3 found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$4 found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) 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-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) 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-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.6.0 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.0)

     Go to the documentation to learn how to <a href="d.android.com/r/tools/classpath-sync-errors">Fix dependency resolution errors</a>.

I tried to restart my pc and flutter clean but that didnt work.

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2

Answers


  1. 0

    Welcome to StackOverflow.

    Possible solution 1
    Your description is insufficient for anyone to tell what might be wrong with your application, except that you might be defining an existing class name.

    If you are sure you didn’t override any Dart class name, and if you are using Visual Studio Code, try to delete your ".dart_tool" folder from your project.

    Then you need to run the flutter pub get to fix all your dependencies and rebuild the necessary folders.

    Possible solution 2
    You might have a library conflict. try to remove some of the latest packages you’ve added, to figure out which ones are conflicting with each other.

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  2. 0

    I think inside android/app/src/main/java there is a main file and also inside android/app/src/main/kotlin there is a main file. So the flutter framework is now confused which entry point should be used as both of them have the same name but in different language. Just remove one of the file and it shoudld work.

    Or, you are using 2 versions of JDKs, just remove one of them

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