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.
Drools is a Java Rule Based Engine. The main purpose of Drools is to keep away the dynamically changing code from the static one. It is done so that when we change the code thereafter, it doesn't require re-compiling or redeployment.