#abstract method in java

Java, being an object-oriented programming language, provides powerful features to support abstraction, encapsulation, inheritance, and polymorphism. One key feature that contributes to achieving these principles is the concept of abstract methods. In this blog post, we'll delve into what abstract methods in Java are and how they play a crucial role in designing flexible and extensible code.

What is an Abstract Method?

In Java, an abstract method is a method declared in an abstract class but lacks a concrete implementation in that class. The abstract keyword is used to define such methods, and they are intended to be implemented by non-abstract (concrete) subclasses. Essentially, abstract methods serve as placeholders or blueprints for functionality that must be defined in subclasses.

Abstract Classes and Their Purpose

To comprehend abstract methods fully, we need to understand abstract classes. An abstract class in Java is a class that cannot be instantiated on its own but serves as a base for other classes. It may contain both abstract and non-abstract (concrete) methods. Abstract methods declared in an abstract class act as a contract, mandating that any concrete subclass must provide an implementation for those methods.

Let's illustrate this with an example:

In this example, Shape is an abstract class with an abstract method draw() and a non-abstract method display(). The draw() method serves as a blueprint for drawing a shape, leaving the specific implementation to its subclasses.

Subclassing and Implementation

Concrete subclasses extending an abstract class must provide implementations for all the abstract methods declared in the superclass. Failure to do so will result in a compilation error. This ensures that all subclasses adhere to the contract specified by the abstract class.

In this example, the Circle class extends the Shape abstract class and provides an implementation for the abstract draw() method. This allows us to create specific shapes with their unique drawing logic while benefiting from the shared functionalities defined in the abstract class.

Advantages of Abstract Methods

Code Reusability: Abstract methods promote code reusability by defining a common interface in the abstract class, allowing multiple subclasses to provide their implementations.

Polymorphism: Abstract methods contribute to achieving polymorphism, allowing objects of different classes to be treated interchangeably based on their common abstract type.

Abstraction: They enable a higher level of abstraction by defining a general structure in the abstract class and leaving specific details to be implemented in subclasses.

Conclusion

In conclusion, abstract methods in Java serve as a powerful mechanism for designing extensible and maintainable code. They provide a blueprint for functionality in abstract classes, ensuring that concrete subclasses adhere to a specified contract. By embracing abstract methods, Java developers can create hierarchies of classes that promote code reusability, polymorphism, and a clearer separation of concerns in their applications.

Abstraction in Java

Abstraction is a concept to show only essential detail i.e hide internal detail and show functionality in simple terms. To achieve abstraction in Java, use abstract class or interface.

Example: In ATM we don’t know how internally work. In a Car don’t know about the internal mechanism.

Ways to achieve Abstraction

We can achieve abstraction in two ways:

Abstract class:abstractio…