Kotlin traits and retrofit

Question

I'm trying to implement the example from here in Kotlin. I get this error at runtime "Caused by: java.lang.IllegalArgumentException: Interface definitions must not extend other interfaces". Is there any way to treat Kotlin traits as java interfaces when they don't have any methods implemented, or do I have to use java interfaces? Here's the code:

public trait RestAPI {

    [GET("/weather")]
    fun getList([Query("q")] place: String,
                [Query("units")] units: String)
            : Observable<WeatherData>
}            

And the call that causes the error:

val service = restAdapter?.create(javaClass<RestAPI>())

Answer 1

This issue has been fixed. I am using Retrofit implemented exactly this way with Kotlin version 0.9.976.