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.
There are a lot of posts regarding thin drivers in this forum. PErhaps you should take some time to search this forum for a detailed explanation. A Thin Driver is otherwise known as a Type IV driver. This is a driver written in pure java and therefore portable across all machines. The classes that communicate with the database are written in java and as such do not require any other component (like the database's client software) to be installed on the application server. Thats the reason behind calling then 'thin'.