Prove that ConcurrentHashMap class behaves like fail safe iterator?

Example -

import java.util.concurrent.ConcurrentHashMap; import java.util.Iterator; public class ConcurrentHashMapExample { public static void main(String[] args) { ConcurrentHashMap<String,String> premiumPhone = new ConcurrentHashMap<String,String>(); premiumPhone.put("Apple", "iPhone6"); premiumPhone.put("HTC", "HTC one"); premiumPhone.put("Samsung","S6"); Iterator iterator = premiumPhone.keySet().iterator(); while (iterator.hasNext()) { System.out.println(premiumPhone.get(iterator.next())); premiumPhone.put("Sony", "Xperia Z"); } } }