There are a lot of pointless comparison based on lines of code on the Internet. It is true that you can do the same task in Ruby in 2-3 lines and could take 20 in Java and the ruby code will still be very well written, clear and maintainable. But across the board LOC comparisons don't have much value. Any first year CS student can tell you that LOC isn't everything.
Even though this is from the official Ruby site, I believe that this is one of the most fair, although very short, comparisons around.
http://www.ruby-lang.org/en/documentation/ruby-from-other-languages/ [ June 13, 2008: Message edited by: Rusty Shackleford ]