what will be the output of following java code?

Problem statement:
what will be the output of the following java code?

1. import java.util.ArrayList;
2. import java.util.Collections;
3. import java.util.HashMap;
4. 
   
5. public class Solutions{
6.     public static void main(String[] args) {
7.         HashMap<Integer, String> m = new HashMap<>();
8.         m.put(1001,"A");
9.         m.put(1002,"B");
10.         Collections.unmodifiableMap(m);
11.         m.put(1001,"C");
12.         System.out.println(m);
13.     }
14. }

Output: {1001=C, 1002=B}