A task has no internal parts, it represents a single unit of work. A task can be run automatically (Script, or BusinessRule) or require completion (Task, ServiceTask, and UserTask) outside of the engine.
This is a generic representation of a task.
This task represents work done by a human user.
This task represents work done by a ruby service proc when supplied to the context.
This task represents work done by the execution process engine written in FEEL.
This task represents work done by the execution rule engine, generally, a complex decision.