package com.nishith.java.collections; import java.util.Iterator; import java.util.concurrent.ConcurrentHashMap; public class FailSafe { public static void main(String[] args) { ConcurrentHashMap map = new ConcurrentHashMap(); map.put("key1", "value1"); map.put("key2", "value2"); map.put("key3", "value3"); Iterator iterator = map.keySet().iterator(); while (iterator.hasNext()) { System.out.println(map.get(iterator.next())); map.put("key4", "value4"); map.put("key5", "value5"); map.put("key6", "value"); } } }