Unified Modeling Language Reference Manual, The, Second Edition

exception

An indication of an unusual situation raised in response to behavioral faults by the underlying execution machinery or explicitly raised by an action. The occurrence of an exception aborts the normal flow of control and causes a search for an exception handler on an enclosing activity node.

Semantics

An exception is an indication that an abnormal situation has occurred that prevents normal execution from occurring. An exception is usually generated implicitly by underlying implementation mechanisms in response to a failure during execution. For example, an attempt to use an invalid array index to access an array element may be treated as an exception. An exception can also be explicitly raised by an action. Such “soft exceptions” can ...