Can anyone explain nonpredefine exception with real world example

Question

Can anyone explain nonpredefine exception with real world example

Answer 1

Is this what you mean?
i.e. When others catches all errors - so it is not predefined
Predefined errors are things like no rows, too many rows etc - meant to catch specific errors
It is the difference between tolerating one 'bad' thing specifically and tolerating all 'bad' things.
DECLARE
   v_text  varchar2(1);
BEGIN
   v_text:= 'THIS STRING IS TOO LONG FOR THIS VARIABLE';
EXCEPTION
   WHEN OTHERS --this is non error specific and generally VERY BAD practise as it suppresses all errors
       dbms_output.put_line('Whatever you want to do when an unknown error manifests here');
END;