The subprocess represents a group of tasks which act together to perform a part of the process.
BPMN element: <bpmn2:callActivity>.
Description: Lets you call a process whose definition resides outside the current process.
Configuration: Use CalledElement, Independent, and WaitForCompletion to configure which existing process definition to call and how to call it: as part of the calling process or as a new process instance (Independent), in a synchronous or asynchronous fashion (WaitForCompletion). Use Assignments, DataInputSet, and DataOutputSet to map variables from/to the calling process.
BPMN element: <bpmn2:subProcess>
Description: Lets you loop (create multiple instances of a group of elements)
Configuration: Use CollectionExpression, Variable Definitions, and Variable Name to configure the loop and assign the variable to pass inside the loop
BPMN element: <bpmn2:adHocSubProcess>
Description: Lets you define an unstructured subprocess definition
Configuration: The AdHoc ordering attribute tells the engine to execute a multi-instance subprocess in parallel or sequentially
BPMN element: <bpmn2:subProcess>
Description: Lets you define an embedded process definition (not reusable from other process definitions)
Configuration: Variable definitions lets you configure variables at the subprocess scope
BPMN element: <bpmn2:subProcess>
Description: Lets you define an embedded subprocess that can be triggered by a specific event (for example, Signal) and is executed in an asynchronous fashion
Configuration: No specific configuration required
