Concurrent. ConcurrentHashMap class achieves thread-safety by dividing the map into segments, the lock is required not for the entire object but for one segment, i.e one thread requires a lock of one segment. In ConcurrenHashap the read operation doesn’t require any lock. Why is Conduplicatio used? .

Is ConcurrentHashMap thread-safe?

Key points of ConcurrentHashMap: ConcurrentHashMap class is thread-safe i.e. multiple threads can operate on a single object without any complications. … The default concurrency-level of ConcurrentHashMap is 16.

How does ConcurrentHashMap achieve thread safety?

ConcurrentHashMap achieves thread safety by dividing the map into segments and locking only the segment which requires instead of locking the whole map. So, yes, it achieves thread safety using locking but it performs better because, unlike HashMap, it never locks the whole map.