Warning: Kotlin JAR files must have the same version to run on the classpath

Question

I get the following warning, but I'm not sure where v1.0.6 is located.

Is it possible that this error comes from the Kotlin library, one way or another, including the old version of Kotlin?

Any ideas on how to fix this, or at least how can I follow the suggestion to make kotlin-reflect explicit (1.1)?

Answer 1

It seems your project is set up in such a way that you are dependent on kotlin-stdlib 1.1 and kotlin-reflect 1.0. The most likely case is that you already have an explicit dependency on kotlin-stdlib 1.1, but have no dependency on kotlin-reflect , and some other library (which you depend on) depends on kotlin-reflect 1.0.

If this is true, the solution should provide explicit dependency on kotlin-reflect 1.1.

In Maven, add this to pom.xml :

  <dependencies> <dependency> <groupId>org.jetbrains.kotlin</groupId> <artifactId>kotlin-reflect</artifactId> <version>1.1.0</version> </dependency> </dependencies> 

In Gradle, add this to build.gradle :

 dependencies { compile "org.jetbrains.kotlin:kotlin-reflect:1.1.0" } 

See information on this and related warnings in white papers .

Answer 2

I fixed the warning by rewriting the kotlin version used in my application

 configurations.all { resolutionStrategy.eachDependency { DependencyResolveDetails details -> def requested = details.requested if (requested.group == 'org.jetbrains.kotlin' && requested.name == 'kotlin-reflect') { details.useVersion kotlin_version } } } 

e.g. kotlin_version = 1.3.0

Answer 3

I ran into the same problem, but it was due to a wrong dagger injection

Answer 4

this happens when you use a dagger in a kotlin (android) project and you have kotlin version 1.7, i.e.

 implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version" 

all you have to do is add the dependency below to your application’s fitness level

  implementation "org.jetbrains.kotlin:kotlin-reflect:1.3.50"