Abstract Class
An abstract class is a class in object-oriented programming that cannot be instantiated directly and is designed to be inherited by other classes. It typically contains one or more abstract methods (methods declared without implementation) that must be implemented by its subclasses, along with possible concrete methods with full implementations. This concept is used to define a common interface and shared behavior for a group of related classes, promoting code reusability and enforcing a contract for derived classes.
Developers should use abstract classes when they need to create a base class that provides a common structure and default functionality for a family of related classes, while requiring specific implementations for certain methods in subclasses. This is particularly useful in scenarios like designing frameworks, implementing design patterns (e.g., Template Method), or ensuring consistency across multiple classes in large-scale applications, as it reduces code duplication and enforces adherence to a defined interface.