java - listIterator API 描述的含义是什么？

Question

这个 API:

/// Returns a list iterator of the elements in this list (in proper sequence)
public ListIterator<E> listIterator(int index)

正确顺序是什么意思？

List<Integer> list = new ArrayList<Integer>();
list.add(1);
list.add(2);
list.add(3);

// Is the sequence returned by i1 and i2 is the same?
ListIterator<Integer> i1 = list.listIterator();
ListIterator<Integer> i2 = list.listIterator();

i1.next();

int result = i1.next(); // Is result 2? Or random?

Answer 1

当在ListIterator对象中迭代时返回索引的正确顺序意味着，和i1，i2是独立的:

import java.util.ArrayList;
import java.util.List;
import java.util.ListIterator;

public class Main
{
    public static void main(String[] args)
    {
        List<Integer> list = new ArrayList<Integer>();
        list.add(1);
        list.add(2);
        list.add(3);

        // Is the sequence returned by i1 and i2 is the same?
        ListIterator<Integer> i1 = list.listIterator();
        ListIterator<Integer> i2 = list.listIterator();

        while (i1.hasNext())
        {
            System.out.println(i1.next());
        }
        while (i2.hasNext())
        {
            System.out.println(i2.next());
        }    
    }
}

输出是:

1
2
3
1
2
3