Java Difference between Hashtable and Hashmap / Hashtable versus Hashmap

Both Hashtable and Hashmap are Hashtable implementation of java classes. Hashtable is a basic class of java 'Collection Framework' and Hashmap is a Hashtable implementa from Map interface.
The majore differences are described below...

1. Synchronous/asynchronous: Hashtable is synchronous and Hashmap is not synchronous by default.

2. null value as key: Hashtable does not support null value as hash key but Hasmap support it.

3. Faile-safe: Iterator of Hashmap is fail-safe but Enumeration of Hashtable is not failsafe.

Perhaps this will be able to eliminate any misconception about Hashtable and Hashmap