Implementing Java Interface - Kotlin

Just getting started with Kotlin and and I have read the official documentation, I am having issues implementing an interface from a library in kotlin.

Here is the interface in java :

public interface ResultCallBack {
    void detailsRetrieved(Obj var1, AnotherInterface var2);

    void anotherDataRetrieved(int var1, AnotherInterface var2);
}

the method I am calling from kotlin is like this :

 public static void startLibActivity(Context context, ResultCallBack callback) {
        sLuhnCallback = callback;
        context.startActivity(new Intent(context, Library.class));
    }

how do i call startLibActivity from kotlin and implement ResultCallBack as well

I think I am stuck with this trial :

Library.startLibActivity(activity, {})

I have tried many possibilities within {} , still having issues with the right implementation.