Class & Object Design Framework

Class design fails when public fields replace private fields with getters and setters, when classes accumulate unrelated responsibilities because "it was easy to add here," and when subclasses override behavior in ways the base class doesn't expect. The class that looks like it follows OOP principles but exposes its entire internal state through getters, accepts mutation of any field through setters, and has 20 methods that span multiple responsibility domains is not an encapsulated class — it's a namespace.

The Class Design Framework applies encapsulation, SOLID principles, and composition-over-inheritance to produce classes that are cohesive, testable, and stable against changes in their dependencies.