What mechanisms ensure thread safety in ConcurrentHashMap?

ConcurrentHashMap in Java provides thread safety through its internal structure and algorithms, allowing multiple threads to read and write to the map simultaneously without locking the entire structure.

Main mechanisms:

• Segmentation (in older versions): the map was divided into several segments, each locked separately, reducing contention.
• CAS operations (Compare-And-Swap): atomic compare and swap are used for updating values, avoiding locks.
• Lock-free reading: read operations do not lock the map, increasing performance.
• Internal bucket-level locks: when updating the structure (e.g., adding a new element), only a small section is locked.

Thus, ConcurrentHashMap ensures high performance and safety when working with multiple threads, minimizing locks and using atomic operations.