The Map interface in Java, part of the java.util package, represents a collection of key-value pairs. It is not a subclass of the Collection interface, unlike List or Set. The Map interface allows storing unique keys, each mapped to a specific value. Common operations provided by the Map interface include adding entries (put()), retrieving values (get()), removing entries (remove()), and checking for the existence of keys or values (containsKey(), containsValue()).
Key Features:
Unique Keys: Each key in a map is unique, but values can be duplicated.
Efficient Lookup: Map offers efficient access to values via keys.
Various Implementations: Implementations like HashMap, TreeMap, LinkedHashMap, and Hashtable offer different performance characteristics.
Common Methods:
put(K key, V value)
get(Object key)
remove(Object key)
containsKey(Object key)
keySet(), values(), entrySet()
Example Implementation:
HashMap: Provides constant-time performance for get() and put() operations.
TreeMap: Orders keys in natural or custom order, with logarithmic time complexity for basic operations.
In summary, the Map interface is a fundamental part of Java’s collection framework, allowing for efficient management of key-value pairs with a variety of implementation choices depending on the use case.
