The Flexibility of Java Inheritance: The Power of Polymorphism

The flexibility of Java inheritance plays an important role in object-oriented programming. Polymorphism, as a form of inheritance, has powerful functions and power. Through polymorphism, we can achieve different performances of the same interface and improve code reusability and scalability. This article will delve into the flexibility of Java inheritance and the power of polymorphism, and help you understand the application and advantages of these concepts in actual development. Let us follow PHP editor Xiaoxin to uncover the mystery of Java inheritance and explore the charm of polymorphism.

Polymorphism is based on two concepts:

• Subclassing: Subclasses can inherit the properties and methods of the parent class and add their own specific implementations.
• Method overriding: Subclasses can override methods inherited from parent classes and provide their own implementations.

Polymorphism occurs when a parent class reference points to an object of its child class. At this point, the parent class reference can call the specific implementation of the child class, even if the parent class is not aware of the existence of the child class.

Benefits of polymorphism

Polymorphism provides the following benefits:

• Code reusability: Common code can work with different types of objects, thereby improving reusability.
• Extensibility: New types can be easily added without modifying existing code.
• Less coupling: Code is loosely coupled to specific types, improving flexibility.
• Readability: The code is easier to read and understand because the focus is on behavior rather than specific types.

How to achieve polymorphism

In Java, polymorphism can be achieved by following these steps:

• Define a base class (parent class) that contains the properties and methods to be shared.
• Create subclasses that inherit the base class and provide specific implementations.
• Use polymorphism to operate subclass objects through parent class references.

An example of polymorphism

Consider an animal base class that has a speak() method. We can create subclasses Dog, Cat, and Bird that implement the speak() method to bark, meow, and chirp respectively. Using polymorphism, we can create a forEachAnimal(Animal animal) method that calls the speak() method regardless of the type of animal.

public class Animal {
public void speak() {}
}

public class Dog extends Animal {
@Override
public void speak() {
System.out.println("Woof woof!");
}
}

public class Cat extends Animal {
@Override
public void speak() {
System.out.println("Meow Meow!");
}
}

public class Bird extends Animal {
@Override
public void speak() {
System.out.println("Squeak!");
}
}

public class PolymorphismDemo {
public static void forEachAnimal(Animal animal) {
animal.speak();
}

public static void main(String[] args) {
Animal[] animals = {new Dog(), new Cat(), new Bird()};
for (Animal animal : animals) {
forEachAnimal(animal);
}
}
}

In this example, the forEachAnimal() method can accept any object of type Animal regardless of its specific type. This shows how polymorphism can make code more flexible and reusable.

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