Sealed classes in Java let developers limit the creation and use of subclasses and preserve the class hierarchy. Here is how sealed classes in Java work.

Compare inheritance and composition, the two fundamental ways to relate Java classes, then practice debugging ClassCastExceptions in Java inheritance.

Inheritance can descend through multiple levels, leading to ever-more-specific categories. As an example, Figure 1 shows car and truck inheriting from vehicle; station wagon inheriting from car ...