map contains values on the basis of key, i.e. key and value pair. Each key and value pair is known as an entry. A Map contains unique keys.
A Map is useful if you have to search, update or delete elements on the basis of a key.
The java.util.Map interface represents a mapping between a key and a value. The Map interface is not a subtype of the Collection interface. Therefore it behaves a bit different from the rest of the collection types.
Few characteristics of the Map Interface are:
This is a companion discussion topic for the original entry at http://iq.opengenus.org/map-java/