jBPM is a lightweight and embeddable Business Process Engine. In the same way that Drools allows us to define declarative knowledge, jBPM allows us to define business process models that can be executed and automated. Luckily for us, Business Processes are more evolved than rules in the sense that they have a whole methodology defined around them. This methodology (also known as a discipline) is called Business Process Management (BPM) and it describes the whole life cycle of how to discover, formalize, execute, and monitor our business processes. You can find more about BPM here: https://en.wikipedia.org/wiki/Business_process_management.
Instead of using the DRL language, jBPM uses the standard notation called BPMN v2 (Business Process Modeling and Notation Version 2, defined by the OMG group) to define business process models. These models have a completely different nature from rules, in the sense that the former have a graphical representation (in contrast...