Java Map types

Mutable maps supports modification operations such as add, remove, and clear on it . Unmodifiable Maps are “read-only” wrappers over other maps. They do not support add, remove, and clear operations, but we can modify their underlying map.

HashMap containsValue() Method in Java util. HashMap. containsValue() method is used to check whether a particular value is being mapped by a single or more than one key in the HashMap. It takes the Value as a parameter and returns True if that value is mapped by any of the key in the map.

HashMap containsValue() Method in Java util. HashMap. containsValue() method is used to check whether a particular value is being mapped by a single or more than one key in the HashMap. It takes the Value as a parameter and returns True if that value is mapped by any of the key in the map.

Mutable maps supports modification operations such as add, remove, and clear on it . Unmodifiable Maps are “read-only” wrappers over other maps. They do not support add, remove, and clear operations, but we can modify their underlying map.

We can also initialize the map using the double-brace syntax: Map<String, String> doubleBraceMap = new HashMap<String, String>() {{ put(“key1”, “value1”); put(“key2”, “value2”); }};

Generally if there is no collision in the hashing value of the key then the complexity of the the containskey is O(1) . The complexity can be understood by seeing how the method has been implemented. The Hashmap contains array of nodes.

Generally if there is no collision in the hashing value of the key then the complexity of the the containskey is O(1) . The complexity can be understood by seeing how the method has been implemented. The Hashmap contains array of nodes.