Is there any difference between ConcurrentHashMap and Collections synchronizedMap

Question

What are the differences between Maps returned by Collections.synchronizedMap(Map) and ConcurrentHashMaps? Which one fits which situation?

Answer 1

ConcurrentHashMap: It allows concurrent modification of the Map from several threads without the need to block them.

Collections.synchronizedMap(map): It creates a blocking Map which will degrade performance, albeit ensure consistency (if used properly).