What is Concurrency HashMap in Java?

How HashMap works in Java

HashMap  works on principle of hashing, we have put() and get() method for storing and retrieving object form HashMap .When we pass an both key and value to put() method to store on HashMap , it uses key object hashcode() method to calculate hashcode and they by applying hashing on that hashcode it identifies bucket location for storing value object. While retrieving it uses key object equals method to find out correct key value pair and return value object associated with that key. HashMap  uses linked list in case of collision and object will be stored in next node of linked list. Also HashMap stores both key and value tuple in every node of linked list in form of Map.Entry object.