   Hashtable, HashMap
  Could someone tell me what the difference is between the Hashtable Java class and the HashMap class?  How do I know when to use which?Also, I have a situation where some hash values will have the same key.  What is the best way of storing multiple values for a given key?  Is it to just throw in a Vector object, or is there something more elegant?Thanks.Mike C.http://www.coolgroups.com/zoomer/   
  "The HashMap  class is roughly equivalent to Hashtable, except that it is unsynchronized and permits nulls."Javadocs.   