What is the difference between Hashtable and HashMap?
Both Hashtable and HashMap store key-value pairs but they have following distinctive features:
-Hashtable is synchronized while HashMap is not.In such a case Hashtable has performance overhead and should only be used when data is to be accessed in thread safe manner.
-In Hashtable any non-null object can be used as a key or as a value but HashMap allows null keys and values.
-Hashtable is synchronized while HashMap is not.In such a case Hashtable has performance overhead and should only be used when data is to be accessed in thread safe manner.
-In Hashtable any non-null object can be used as a key or as a value but HashMap allows null keys and values.
