This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Seriously. You'll do yourself a favor by learning to use Google. The first hit for "jython" goes directly to the right place, the Jython website, and there the first link on the front page says "What is Jython?. For this kind of questions, Google will help you ten times faster and better than any discussion forum can.