The API of KnowledgeBase and *KnowlegdeSession should clearly document if it is thread-safe or not. --------------------------------------------------------------------------------------------------- Key: DROOLS-756 URL: https://issues.jboss.org/browse/DROOLS-756 Project: Drools Issue Type: Task Components: core engine Reporter: Geoffrey De Smet Assignee: Edson Tirelli Priority: Optional See http://stackoverflow.com/questions/3817639/best-practices-for-using-drool... If it depends on the method the main class header should state it does and each method should state if it's thread safe or not.