Java: Sealed Classes

By limiting subclassing to specific classes.

Sealed classes enforce architectural constraints by allowing only specified classes to extend them, thereby shaping the overall architecture. This constraint is beneficial in large systems where maintaining consistency and preventing misuse is crucial. In an e-commerce system, a sealed class `Product` might allow only `PhysicalProduct` and `DigitalProduct` to extend it, ensuring that all products adhere to the same rules and logic.