A HashMap is a part of Java’s Collection Framework and implements the Map interface. It stores elements in key-value pairs, where, Keys are unique. and Values can be duplicated. Internally uses Hashing, hence allows efficient key-based retrieval, insertion, and removal with an average of O (1) time.

The HashMap class of the Java collections framework provides the functionality of the hash table data structure. It stores elements in key/value pairs. Here, keys are unique identifiers used to associate each value on a map. The HashMap class implements the Map interface.

Keys: 1, 2, 3, Values: Java, Python, JavaScript, Entries: 1 =Java, 2 =Python, 3 =JavaScript, HashMap in Java stores the elements using key-value mapping, where we can fetch an element from the HashMap using its key.

The Key We can use any class as the key in our HashMap. However, for the map to work properly, we need to provide an implementation for equals () and hashCode (). Let’s say we want to have a map with the product as the key and the price as the value: