Java Create a ConcurrentHashMap

To create a ConcurrentHashMap in Java, you can use the following code:

ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>();

This code creates a new ConcurrentHashMap called map that maps keys of type String to values of type Integer. The ConcurrentHashMap is a class that provides thread-safe access to a hash map, allowing multiple threads to read and write to the map simultaneously without causing data corruption or race conditions.

You can then use the put method of the ConcurrentHashMap to add key-value pairs to the map, like this:

map.put("key1", 10);
map.put("key2", 20);

To retrieve the value associated with a key, you can use the get method, like this:

int value = map.get("key1"); // value will be 10

You can also use the size method to get the number of key-value pairs in the map, and the isEmpty method to check if the map is empty.