title: Pros and cons of Java rules engines
body: <p>What are the pros and cons to adopting the Java rules engines <a href="http://www.jessrules.com/" rel="noreferrer">JESS</a> and <a href="http://www.jboss.org/drools/" rel="noreferrer">Drools</a>? Are there any other players?</p>
  
  <p>I understand that Drools is Open Source and JESS is not, but how do they compare in other areas like ease of use, performance, level of integration with your code?</p>