As far as I know, java.util.Hashtable synchronizes each and every method in the java.util.Map interface, while Collections.synchronizedMap(hash_map) returns a wrapper object containing synchronized methods delegating calls to the actual hash_map (correct me if I am wrong).

I have two questions :

  1. What difference does it make to synchronize each and every method and to have a wrapper class? What are the scenarios to choose one over the other?

  2. What happens when we do Collections.synchronizedMap(hash_table)? Will this be equal to simply using a normal java.util.Hashtable?

java collections synchronization hashmap hashtable
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