How to implement polymorphism in Java language

The Java language is an object-oriented programming language, and polymorphism is one of the important concepts in object-oriented programming. In Java, polymorphism can provide programmers with a more flexible way of organizing code, and can also improve the maintainability and scalability of the program. This article will introduce the implementation method of polymorphism in Java language.

1. What is polymorphism

In Java, polymorphism means that different objects implement the same method through the same interface, but the final results may be different . In this case, the same method will be called by different objects, and the implementation of the method will be different depending on the object. This phenomenon is polymorphism.

2. Polymorphic implementation methods

Java language provides two methods to achieve polymorphism: overloading and overwriting.

2.1 Overloading

Overloading refers to defining multiple methods in a class. These methods have the same name but different parameter lists. The Java compiler distinguishes these methods according to the type and number of the method's parameter list at compile time. Different methods can have different return types. This method overloading method can realize different functions with the same method name.

The following is the implementation of overloading:

public class OverloadExample {
    public void print() {
        System.out.println("I am a dog.");
    }
    public void print(int age) {
        System.out.println("I am a " + age + " years old dog.");
    }
    public void print(String name) {
        System.out.println("I am a dog. My name is " + name + ".");
    }
}

In the above code, we define three different print methods, namely print(), print(int age), and print(String name). The three methods have the same method name, but different parameter lists. In this way, the same method name can be used to implement different functions.

2.2 Overwriting

Overwriting means that the subclass defines a method with the same name as the parent class method, and the parameter list of the method is also the same. When a subclass calls this method, the subclass's method will be called to override the parent class's method. In this way, different objects can call the same method, but the method implementation is different.

The following is the implementation method of coverage:

public class Animal {
    public void print() {
        System.out.println("I am an animal.");
    }
}

public class Dog extends Animal {
    public void print() {
        System.out.println("I am a dog.");
    }
}

In the above code, we define a parent class Animal and a subclass Dog. A print method is defined in Animal, and a print method is also defined in Dog, and the names and parameter lists of the two methods are the same. When we call the print method of the Dog object, the method of the subclass Dog will be called, not the method of the parent class Animal. In this way, different objects can call the same method, but the method implementation is different.

3. Advantages of polymorphism

Using polymorphism can improve the flexibility, maintainability and scalability of the program. Through polymorphism, we can better achieve code reuse and abstraction. Polymorphism can help us better abstract common code logic and apply these logic to different specific implementations. This approach helps make the code more concise, easier to maintain and extend.

4. Summary

In the Java language, polymorphism is an important concept in object-oriented programming. The Java language provides two methods to achieve polymorphism: overloading and overwriting. Using polymorphism can improve program flexibility, maintainability, and scalability. Through polymorphism, we can better achieve code reuse and abstraction.

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