HashMap Vs HashTable

[Shishir malviya]

Can somebody tell me what is the difference between HashMap and hashTable and which one is more better than other and why.

[Priya Jothi]

HashMap & Hashtable both use hashing mechanism and store the entries as key value pairs.The difference between them is hashmap can store one null key & multiple null values,but hashtable doesn't allow anything(either a key or value) which is null.One more difference is hashtable is synchronized where as hashmap is not.Deciding the better one depends on ur design.

Regards,
Priya.

[Ja vardhan]

Jothi,

Can u please explain whats do u mean by "HashMap can hold one null key and multiple null values" ??
Whats the advantage of synchronised HashTable? When can v use it?

Can any one explain this pls...

[Sergei Iakhnin]

Since Hashtable is synchronized it can be used safely in a multithreaded program guaranteeing exclusivity of access to a thread that holds its lock. HashMap does not have this functionality.

[Annette Sovereign]

Ja,

You are allowed only one null key in a HashMap whilst your are not allowed to use null in a HashTable as a key or value.

Hope this helps.

An