Of this abstraction. The values for getRadius() or getCircumference() in the above mentioned case in point might be saved directly, or they could be calculated, it will not matter to your caller; the setters may well or won't have side effects; it doesn't subject for the caller. See @michael-puckett-ii 's https://propertyingurugram.in/we-are-evaluating-new-age-technology-into-new-projects-such-as-virtual-assistants-in-store-stylist-robots/