Keyword & Parameter Description:
WHEN:
This keyword introduces the exception handler. You can have many exceptions execute the similar sequence of the statements by following the keyword WHEN with a list of the exceptions, unraveling them by the keyword OR. When any exception in the list is raised, the related statements are executed.
exception_name:
This identifies a predefined exception like ZERO_DIVIDE, or a user-defined exception formerly declared within the present scope.
OTHERS:
This keyword stands for all the exceptions not explicitly named in the exception-handling section of the block. The use of OTHERS is optional and is permitted only as the last exception handler. You cannot involve OTHERS in the list of exceptions subsequent the keyword WHEN.
Statement:
This is merely an executable statement.