Abstract Class in Java

In object-oriented programming, an abstract class is a type of class that cannot be instantiated directly but serves as a blueprint for other classes. Abstract classes are designed to be inherited by other classes, providing a common structure and behavior that can be shared among multiple subclasses. Abstract classes in languages such as Java and C++ play a crucial role in implementing class-based inheritance.

They serve as a main abstraction for polymorphism and modular programming, allowing for the reduction of complexity in software development. By defining abstract classes, developers can create a foundation for other classes to build upon.Abstract classes act as a template or contract, specifying common methods and properties that subclasses must implement.

This allows for code reuse and promotes modular programming, as subclasses can inherit the characteristics of the abstract class while also adding their own unique properties and behavior. Abstract classes are created using the "abstract" keyword in most programming languages. In addition to serving as a blueprint for subclasses, abstract classes can also be used to define abstract methods. Abstract methods are methods that do not have an implementation in the abstract class and must be implemented by any concrete subclass. This flexibility allows for further customization and specialization of the classes that inherit from the abstract class. Abstract classes also play a significant role in polymorphism.

Difference between abstract class and concrete class

One of the main differences between an abstract class and a concrete class is that an abstract class cannot be directly instantiated, while a concrete class can be instantiated and used to create objects. Another difference is that an abstract class can have both concrete and abstract methods, whereas a concrete class only contains concrete methods with actual implementations. Abstract classes serve as a higher level of abstraction, providing a common interface and behavior that subclasses can inherit and implement. Abstract classes are often used in inheritance hierarchies, where the abstract class acts as a superclass and provides common behavior and structure for its subclasses

Differences between interfaces and abstract classes

While abstract classes and interfaces serve similar purposes in object-oriented programming, there are some key differences between them. Interfaces are purely abstract and cannot contain any concrete methods or code, whereas abstract classes can have both concrete and abstract methods. Abstract classes are used in inheritance hierarchies, where the abstract class is a superclass and subclasses inherit its abstract operations (Sejans & Nikiforova, 2011). On the other hand, interfaces are used to define a contract or set of rules that a class must adhere to