|No method in HashMap are synchronized.
||All methods in HashTable are synchronized.
|HashMap is not theread safe because multiple thereads can operate on HashMap object simultaneously.
||HashTable is thread safe because at a time only one thread is allowed to operate on HashTable object.
|Performance is high since theread are not required to wait.
||Performance is low since it increases the waiting time of a thread.
|Null is allowed for both key and value.
||Null is not allowed for both key and value.
|It is non legacy class. Introuduce in Java 1.2
||It is legacy class. Introuduce in Java 1.0