Question 1 (Array-Length):
can i assume that this means that there must be an array of 7 elements (number of fields).
Question 2 (Reasons for an error):
Since the specification of find says, fields with null values can be ignored and in the specification of update there is nothing stated about null values, is this a case of an error.
Another case of an error is when i field that has the length of 8 has to be updated with a string that has the length of 10 and the last reason for an error is if there is specified that a field can only have the value Y and N and there comes another value.
Question 3 (Error handling):
But what about invalid values, like A for the Y/N - field?
In the book of A. Monkhouse is mentioned to bypass this situation with a RuntimeException, since we cannot extend the interface. My solution would by to introduce a InvalidArgumentException that extends from RuntimeException.