Of the abstraction. The values for getRadius() or getCircumference() in the above mentioned instance can be saved straight, or they could be calculated, it does not matter on the caller; the setters might or may not have Unwanted effects; it isn't going to issue to your caller. See @michael-puckett-ii 's https://propertyingurugram.in/this-navratri-real-estate-developers-hand-out-special-cash-discounts-and-offer-to-buyers/