What is the relationship between BPMN and UML?
UML is a general-purpose modeling language for software-intensive systems with thirteen diagram types, whereas BPMN is a domain-specific modeling language for business processes with one diagram type (the Business Process Diagram or BPD). Although the BPMN BPD shares many concepts and constructs with UML Activity diagrams, there are also many significant differences between the two languages. At least two UML vendors have defined UML profiles (customizations) for BPMN, which define mappings between BPMN notation and UML notation and semantics.