Enthuware

How all of these code snippets given in options 1, 2, and 3, can be appropriate? All methods are public and for such cases we should throw exceptions, not assert errors. The same explanation could be found in other similar questions.

This is as per Oracle's official recommendations given here: http://docs.oracle.com/javase/7/docs/te ... html#usage

The cases given in this code fall under the "Class Invariants" category.

HTH,
Paul.

thanks, now it's clear