import java.util.ArrayList; | |
import java.util.HashMap; | |
import java.util.List; | |
import java.util.Map; | |
class Demo { | |
public static void main(String[] args) { | |
Function<? super String, ? extends List<String>> mappingFunction = key -> new ArrayList<>(); | |
} | |
interface Function<T, R> { | |
public R apply(T t); | |
} | |
} |