How HashMap works in Java ?
A HashMap in Java stores key-value pairs. The
HashMap requires a hash function and uses
hashCode and equals methods, in order to put and retrieve elements to and from the collection respectively. When the put method is invoked, the
HashMap calculates the hash value of the key and stores the pair in the appropriate index inside the collection. If the key exists, its value is updated with the new value. Some important characteristics of a
HashMap are its capacity, its load factor and the threshold resizing.