Generics questions

 Question 1:

package generics;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<?> list = Arrays.asList(1, "hello", 2.2);
        List<Object> list2 = list;
    }

//    public static void reverse(List<?> list) {
//        List<Object> tmp = new ArrayList<>(list);
//        for (int i = 0; i < list.size(); i++) {
//            list.set(i, tmp.get(list.size() - i - 1)); // compile-time error }
//        }
//    }

    public static void foo2(List<?> list) {
        List<?> tmp = new ArrayList<>(list);
        for (int i = 0; i < list.size(); i++) {
            list.set(i, tmp.get(list.size() - i - 1));
        }
    }

    public static void foo(List<?> list) {
        rev(list);
    }

    private static <T> void rev(List<T> list) {
        List<T> tmp = new ArrayList<>(list);
        for (int i = 0; i < list.size(); i++) {
            list.set(i, tmp.get(list.size() - i - 1));
        }
        System.out.println(list);
    }

    private static <T> void parvin(List<T> list) {
        List<Object> tmp = new ArrayList<>(list);
        for (int i = 0; i < list.size(); i++) {
            list.set(i, tmp.get(list.size() - i - 1));
        }
        System.out.println(list);
    }

}