Of this abstraction. The values for getRadius() or getCircumference() in the above mentioned example may very well be saved directly, or they might be calculated, it would not issue to the caller; the setters could or might not have Uncomfortable side effects; it does not issue towards the caller. [1] https://propertyingurugram.in/why-m3m-altitude-sector-65-stands-as-gurgaons-landmark-of-luxury/