How to prevent ConcurrentModificationException when using Iterator in a Java ConcurrentHashMap?
I'm having trouble with I'm reviewing some code and I'm trying to implement I can't seem to get After trying multiple solutions online, I still can't figure this out....... I'm working with a `ConcurrentModificationException` while iterating over a `ConcurrentHashMap` in Java, specifically when trying to remove elements during the iteration. I'm using Java 11 and the following code snippet demonstrates the scenario: ```java import java.util.Iterator; import java.util.concurrent.ConcurrentHashMap; public class Example { public static void main(String[] args) { ConcurrentHashMap<Integer, String> map = new ConcurrentHashMap<>(); map.put(1, "One"); map.put(2, "Two"); map.put(3, "Three"); Iterator<Integer> iterator = map.keySet().iterator(); while (iterator.hasNext()) { Integer key = iterator.next(); if (key.equals(2)) { map.remove(key); // This line causes ConcurrentModificationException } System.out.println(key); } } } ``` I assumed that since `ConcurrentHashMap` is designed for concurrent access, I could safely remove entries from it while iterating. However, the exception occurs when I try to remove an element. I've tried using the `remove` method of the iterator itself, but it doesn’t seem to work because I'm using a key set iterator here. Should I use a different approach? Am I misusing `ConcurrentHashMap`? I've looked into using a `forEach` loop, but it feels less flexible since I need to use conditions for removal directly. What’s the best practice for modifying a `ConcurrentHashMap` during iteration? Any insights or alternative methods would be greatly appreciated! For context: I'm using Java on Windows. What's the best practice here? For context: I'm using Java on Ubuntu. What am I doing wrong? This is for a web app running on CentOS. Any advice would be much appreciated. I'm working in a macOS environment. What are your experiences with this? Any suggestions would be helpful. I'd love to hear your thoughts on this.