Debugging Drools

http://planet.jboss.org/post/debugging_drools_rules
http://stackoverflow.com/questions/19951880/drools-how-to-find-out-which-all-rules-were-matched
http://blog.lunatech.com/2011/09/02/logging-debug-drools

http://docs.jboss.org/drools/release/5.2.0.Final/drools-expert-docs/html/ch05.html#d0e3080

http://blog.athico.com/2011/10/cookbook-how-to-test-rules-using-xunit.html

https://thomassundberg.wordpress.com/2012/10/11/jboss-drools-a-hello-world-example/