From UML 2.5 p. 307:
14.2.3.4.3 State entry, exit, and doActivity Behaviors
A State may have an associated entry Behavior. This Behavior, if defined, is executed whenever the State is entered through an external Transition. In addition, a State may also have an associated exit Behavior, which, if defined, is executed whenever the State is exited.
A State may also have an associated doActivity Behavior. This Behavior commences execution when the State is entered (but only after the State entry Behavior has completed) and executes concurrently with any other Behaviors that may be associated with the State, until:
- it completes (in which case a completion event is generated) or
- the State is exited, in which case execution of the doActivity Behavior is aborted.
The execution of a doActivity Behavior of a State is not affected by the firing of an internal Transition of that State.