What is the purpose of ConcurrentHashMap in Java?

ConcurrentHashMap in Java is a thread-safe hash table that allows concurrent access in a multi-threaded environment without requiring additional synchronization measures. It offers better performance than Hashtable and synchronized HashMap, and supports more concurrent operations.

ConcurrentHashMap is commonly used in concurrent environments that require frequent reads and writes, such as cache systems in high-concurrency web applications. It not only ensures thread safety, but also offers better performance by implementing concurrent read and write operations through segmented locks instead of locking the entire hash table.

In summary, ConcurrentHashMap is used in scenarios that require high levels of concurrent read and write operations, providing improved performance and thread safety.