This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
Depending on what you want to do, there are a couple of options. If by 0 you mean that the hashtable has been created, but nothing is in there, you can do a Hashtable.isEmpty(), which returns true if there is nothing in the hashtable, or false if there is. You can also use Hashtable.size(), which returns the number of keys in your hashtable. This way, if you want to know that there are more than 0, or more than 1, or whatever, you can test for that. Hope that helps Jason