What are the advantages of HashMap over Hashtable?

What are the advantages of HashMap over Hashtable?

HashMap is generally preferred over Hashtable because it is not synchronized, making it faster for non-threaded applications.

Does that mean HashMap is not thread-safe?

Yes, that's correct. HashMap is not thread-safe, while Hashtable is synchronized, which can lead to performance overhead.

Are there any other differences I should know about?

Yes, HashMap allows null keys and values, while Hashtable does not. This can be a significant advantage in many scenarios.

When should I use Hashtable instead of HashMap?

You might choose Hashtable if you need a thread-safe implementation and are working in a multi-threaded environment.