This week's book giveaway is in the Performance forum. We're giving away four copies of The Java Performance Companion and have Charlie Hunt, Monica Beckwith, Poonam Parhar, & Bengt Rutisson on-line! See this thread for details.
No. But that is because you can't do anything with any ResultSet without first moving the cursor to a row. However, you can use a query to find out how many rows a query will return without having to iterate through the whole query ResultSet by using the count SQL function.