Fix React Native Android builds "Duplicate class kotlin.collections.* found in modules jetified-kotlin-stdlib-1.8.0"
Tags: reactnative, android, kotlin, gradle
Published: 2023-01-26 16:53:56

When I got up this morning, I was perplexed to see that our CI/CD builds were failing repeatedly with the following error:

```java
Execution failed for task ':app:checkStagingReleaseDuplicateClasses'.
> A failure occurred while executing com.android.build.gradle.internal.tasks.CheckDuplicatesRunnable
   > Duplicate class kotlin.collections.jdk8.CollectionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
     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-jdk7-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10)
     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-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
     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-jdk7-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10)
     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-jdk7-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10)
     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-jdk7-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10)
     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-jdk7-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10)
     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-jdk7-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10)
     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-jdk7-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10)
     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-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
     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-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
     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-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$1 found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$2 found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$3 found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
     Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$4 found in modules jetified-kotlin-stdlib-1.8.0 (org.jetbrains.kotlin:kotlin-stdlib:1.8.0) and jetified-kotlin-stdlib-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
     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-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
     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-jdk8-1.6.10 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.6.10)
```

I looked for any problems relating to this but came up empty-handed. After making a few attempts, I discovered a workaround:


Your `android/app/build.gradle` file has to be updated in order to align `kotlin-stdlib` versions:

```gradle
configurations.all {
    resolutionStrategy {
        eachDependency {
            if ((requested.group == "org.jetbrains.kotlin") && (requested.name.startsWith("kotlin-stdlib"))) {
                useVersion("1.6.10")
            }
        }
    }
}
```

---

**UPDATE (27-01-2023):**


In the `android/app/build.gradle` file, there is a better way to apply constraints for the two `kotlin-stdlib-jdk7` and `kotlin-stdlib-jdk8` modules:


```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")
        }
    }
```