All, As some of you trying out 3.1M1 already noticed, we were requiring all classes of facts asserted into working memory to have a no-arg default public constructor. This was because shadow facts are implemented as lazy proxies internally in the engine, even not being "accessible" from external world. Today I inlined and integrated Objenesis (http://objenesis.googlecode.com/svn/docs/index.html) into drools-core as a way to avoid that. Objenesis team did a pretty good job in their project and I can say I'm really happy with the results. Facts don't need any special constructor anymore. So far, all my tests passed and I found no problem. Although, I would like to ask those of you trying out new drools version in different environments (Application Servers, Security Managers, OSs and JVMs) to checkout and try trunk code. Please let us know if you encounter any odd exception. Work was done under: http://jira.jboss.com/jira/browse/JBRULES-700 Thank you, Edson -- Edson Tirelli Software Engineer - JBoss Rules Core Developer Office: +55 11 3124-6000 Mobile: +55 11 9218-4151 JBoss, a division of Red Hat @ www.jboss.com