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

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.

Inheritance is problematic because it breaks encapsulation. You will recall from Java 101: Classes and objects in Java that encapsulation refers to combining constructors, fields, and methods into ...