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.
If you want to try JDBC only (not Oracle specific features), there are other options with lesser memory footprints like HSQLDB, Derby etc which are absolute free. Coming to Oracle, I think you can still download a trial version of it.