HashMap Vs HashTable

HashMap and HashTable both implements Map interface but their are some difference between HashMap and HashTable.

1. HashMap is not synchronized whereas HashTable is synchronized.
2. HashMap allows one null key and any number of null values but HashTable does not allow null keys or values.
3. Iterator in HashMap is fail fast but Enumeration in HashTable is not fail fast.

Parameter	Hashmap	Hashtable
Synchronized	Not Syncronized	Syncronized
Null key and Value	Allows one null key and any number of null values	Not allow null keys or values
Fail fast	Iterator in Hashmap is fail fast	Enumeration in Hashtable is not fail fast
ThreadSafe	No	Yes
Extends	Extends AbstractMap class	Extends Dictionary class
Performance	Faster then Hashtable	Slower then Hashmap