无法删除java.util.Map.Entry中的所有元素

Question

In all element in Entry Map, I only can remove the one element at least position. Can anybody explain what reason ?

Ps: I think problem at EntryMap with HashMap

This is full code:

import java.util.HashMap;

import java.util.Map;

import java.util.Map.Entry;

import java.util.Scanner;

public class Neti {

    static Map<Integer, String> mm = new HashMap<>();

    static void removeEntry(Integer val) {

        for (Entry<Integer, String> entry : mm.entrySet()) {

            if (entry.getKey() == val) {

                mm.remove(val);

                break;
            }
        }
    }

    public static void main(String[] args) {
         mm.put(123, "one");
         mm.put(1234, "two");
         mm.put(12345, "three");
         mm.put(123456, "four");

        Scanner scanner = new Scanner(System.in);
        System.out.println("We have: " + mm);
        for (;;) {
            System.out.print("Number to remove: ");

            int val = scanner.nextInt();

            removeEntry(val);
            System.out.println("Map entries are: " + mm.toString());
        }
    }

}

Answer 1

Your entire removeEntry method can be replaced by a single statement - mm.remove(val) . There's no need to iterate over the entrySet to find the key you wish to remove, and even if there was, using == for reference types is usually wrong.