I'm having a strange issue with extending a Kotlin class that implements Iterable. It seems as though when viewed from Java, the implementation clashes with the

java.util

equivalent. Not really too sure what's up!

Because Kotlin generates covariant generic by default

<? extends String>

@JvmSuppressWildcards

worked for me when I tagged the second generic parameter for Map. Thanks! I am a little confused as to what you mean by "use it on the Java side" though, since trying to something like:

public Iterator<Map<String, ? extends String>> iterator() {
    return super.iterator();
}

gives you the same error as before

Oh, I see, yes, you should add @JvmSuppressWildcards in Foo : Iterable