Of the abstraction. The values for getRadius() or getCircumference() in the above mentioned case in point can be saved right, or they might be calculated, it does not subject to the caller; the setters may possibly or might not have side effects; it doesn't matter for the caller. Classic getters https://medium.com/@CentralPark104/a-new-benchmark-in-futuristic-urban-living-smartworld-one-dxp-sector-113-782bf5e5abe7