List<Object>和List<String>

import java.util.*;

public class Test {

    public static void main(String[] args) {
        List<String> str = new ArrayList<>();
        printList(str);
    }

    public static void printList(List<Object> str) {
        Iterator it = str.iterator();
        while(it.hasNext()){
                System.out.println(it.next());
        }
    }
}