Architecting and designing : UML 2.0 Lite : UML models : UML activity diagram : Final action state
  
Final action state
You may model the final state that the system is in when the sequential flow represented by the Activity diagram ends. The final state is represented by a small, filled-in circle (or large bullet) enclosed within a larger thin circle. The definition of a Final Action State is the same as that of an Action State.
See also
UML activity diagram