What he is trying to say over here is that if the TARGET is set to a bean by the expression and the property mentioned in c:set does not exist in the bean then an exception will be caused but EL will simply return null and the result printed will be blank value. So no exception thrown will be shown on the
jsp page.
But in case we are setting the TARGET using the expression and that property, which was supposed to set the value of the TARGET does not exist then it will generate an exception.
Correct me if i am wrong friend .........