Java SE: Polymorphism

Java Fundamentals and Principles

What is the Java Polymorphism OOP paradigm

1 Overview

📘 Polymorphism

Polymorphism is a fundamental concept in object-oriented programming. It is the ability of an object to take on different forms.

In other words, it is the ability of a single object to behave differently in different contexts.

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Polymorphism is an important concept in object-oriented programming because it allows developers to write code that is more flexible and reusable. By using polymorphism, developers can write code that can operate on objects of different types, without knowing the specific type of the object in advance.

Java SE Basic Principles OOP Polymorphishm

In Java, polymorphism is achieved through the use of inheritance and interfaces. A subclass can implement multiple interfaces, and an interface can be implemented by multiple classes. This allows objects of different types to share a common set of methods, which can be called on the objects without knowing their specific type.

Here is an example of polymorphism in Java using the Animal, Dog, and Cat classes from the previous examples:

public class Main {
    public static void main(String[] args) {
        // Create a Dog object
        Dog dog = new Dog("Buddy", 5);

        // Create a Cat object
        Cat cat = new Cat("Whiskers", 3);

        // Call the makeNoise() method on the Dog object
        dog.makeNoise();

        // Call the makeNoise() method on the Cat object
        cat.makeNoise();
    }
}

In this example, the Dog class and the Cat class both implement the Animal class, which defines the makeNoise() method. This means that the Dog and Cat classes both have their own implementations of the makeNoise() method.

When the makeNoise() method is called on the dog object, it executes the implementation in the Dog class, which prints the “Woof!” message to the console. When the makeNoise() method is called on the cat object, it executes the implementation in the Cat class, which prints the “Meow!” message to the console.

2 Conclusion