Why does the same Map.Entry change when calling iterator.remove() in Java TreeMap?

When I use Iterator to iterate some TreeMap, I found the same Map.Entry's content will change. For example:

import java.util.Map.Entry;
import java.util.TreeMap;

public class Solution {
    public static void main(String[] args) {
        TreeMap<Integer, Integer> map = new TreeMap<>();
        map.put(1,1);
        map.put(2,2);
        map.put(3,3);
        System.out.println("map: " + map);
        Map<Integer, Integer> fromMap = map.tailMap(2);
        System.out.println("fromMap: " + fromMap);
        Iterator<Entry<Integer, Integer>> iter = fromMap.entrySet().iterator();
        Entry<Integer, Integer> entry = iter.next();
        System.out.println(entry); // line 1  
        iter.remove();
        System.out.println(entry); // line 2. Why does entry content change?
    }
}

result:

map: {1=1, 2=2, 3=3}
fromMap: {2=2, 3=3}
2=2
3=3

The entry in line 1 and line 2 of the above code has the same reference, however the content changes when I call iter.remove().