How HashMap works in Java

How a HashMap Works internally has become a popular question in almost all the interview. As almost everybody knows how to use a HashMap or the difference between HashMap and Hashtable. But many fails when the question is how does a hashmap internally works.

So the answer to the question how does a hashmap works is that is it works based on the hashing principle but it is not as simple as it sounds. Hashing is the mechanism of assigning the unique code to a variable or attribute using some algorithm to enable easy retrieval. A true hashing mechanism should always return the same hashCode() when it is applied to the same object. [Read more…]