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javaandroidgenericskotlinkotlin-generics

Kotlin Generics Error in Java

Given the following three kotlin classes:

abstract class UseCase<T> {
    fun execute(action: Action<T>) {
    }
}

class ConcreteUseCase : UseCase<List<String>>()

class Action<T>

I am unable to compile following lines in java code:

ConcreteUseCase s = new ConcreteUseCase();
s.execute(new Action<List<String>>());//<<<<<<< compilation error

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Error says:

SomeClass<java.util.List<? extends Type>> in Class cannot be applied to SomeClass<java.util.List<Type>>

I am still new to kotlin and this might be something very small but I can't seem to figure it out. I will appreciate any help.

Solution

  • Change your ConcreteUseCase as following:

    class ConcreteUseCase : UseCase<List<@JvmSuppressWildcards String>>()

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