If the input object is an instantiated Behavior that is not already executing, then it begins executing. If the input object has a classifierBehavior that is not already executing, then it is instantiated and started. In either case ... Source Unified Modeling Language 2.5.1
A StartObjectBehaviorAction is a CallAction that starts the execution either of a directly instantiated Behavior or of the classifierBehavior of an object. The object to be started is taken from the object InputPin. Source Unified Modeling Language 2.5.1
