michiakig

import java.util.*;

public class TypeSafety {

    public static void main(String[] args){
        List<Set<?>> listOfWildcardSet = new ArrayList<Set<?>>();
        listOfWildcardSet.add(new HashSet<String>());
        listOfWildcardSet.add(new HashSet<Integer>());
        listOfWildcardSet.set(0, listOfWildcardSet.get(0));
        listOfWildcardSet.set(1, listOfWildcardSet.get(1));