Enpatika

The Map interface includes methods for basic operations (such as put , get , remove , containsKey , containsValue , size , and empty ), bulk operations (such as putAll and clear ), and collection views (such as keySet , entrySet , and values ).

This implementation provides constant-time performance for the basic operations (get and put), assuming the hash function disperses the elements properly among the buckets. Since containsKey() is just a get() that throws away the retrieved value , it’s O(1) (assuming the hash function works properly, again).

The map interface is present in java. util package 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 differently from the rest of the collection types. A map contains unique keys.

Map , represents a mapping between a key and a value . More specifically, a Java Map can store pairs of keys and values. Each key is linked to a specific value. Once stored in a Map , you can later look up the value using just the key. The Java Map interface is not a subtype of the Collection interface.