The Techno Journals

HashMap is used to store the data in key, value pair where key is unique and value can be store or retrieve using the key. Any class can be a candidate for the map key if it follows below rules. 1. Overrides hashcode() and equals() method.   Map stores the data using hashcode() and equals() method from key. To store a value against a given key, map first calls key's hashcode() and then uses it to calculate the index position in backed array by applying some hashing function. For each index position it has a bucket which is a LinkedList and changed to Node from java 8. Then it will iterate through all the element and will check the equality with key by calling it's equals() method if a match is found, it will update the value with the new value otherwise it will add the new entry with given key and value. In the same way it check for the existing key when get() is called. If it finds a match for given key in the bucket with given hashcode(), it will return the value other...