Abstract classes can provide default behavior and state.
An abstract class can include fields and methods with implementations, allowing shared code among subclasses. This is useful when classes share common behavior or state. For example, an abstract class 'Product' might include a 'name' field and a method 'getDescription' that can be inherited by both 'PhysicalProduct' and 'DigitalProduct' subclasses, reducing code duplication.
Additional Notes
Why might you use an abstract class instead of an interface?