Of the abstraction. The values for getRadius() or getCircumference() in the above mentioned example might be stored directly, or they might be calculated, it doesn't make any difference into the caller; the setters may or may not have side effects; it isn't going to make any difference on the caller. https://propertyingurugram.in/rail-overbridge-ready-but-you-cant-use-it-till-dwarka-e-way-work-ends/