ConcurrentHashMap is a class that implements the ConcurrentMap and serializable interface. We can synchronize the HashMap by using the synchronizedMap() method of java.

Is HashMap synchronized?

HashMap is a non-synchronized collection class.

Which map is not synchronized in Java?

Java HashMap is not synchronized by default. If we add/remove key-value pairs from a HashMap in a concurrent application where multiple threads are adding and removing pairs, we may end up having inconsistent state of the map.