What does superclass mean in java

In Java, superclass is the parent class of a class, specified by the extends keyword. It provides code reuse, organization and polymorphism, allowing subclasses to access superclass members using the super keyword. In overriding, the subclass reimplements the inherited method, whereas in overriding, the subclass adds or modifies functionality while retaining the original implementation.

Superclass in Java

In Java, superclass is the parent class of a class. It defines the properties and methods that subclasses inherit.

Why use superclass?

• Code reuse: Through inheritance, subclasses can reuse the code of the parent class, thereby avoiding duplication of work.
• Organization: Superclass allows you to group classes with similar functionality together, thereby improving the readability and maintainability of your code.
• Polymorphism: superclass allows objects of subclasses to be treated as objects of the parent class, allowing for more flexible and extensible code.

How to define superclass

You can specify a superclass using the extends keyword in the class definition as follows:

class Subclass extends Superclass {
    // 子类代码
}

Accessing superclass members

Subclasses can use the super keyword to access members of their superclass. There are the following two methods:

• Call the superclass method: super.methodName()
• Access the superclass attribute:super.attributeName

##Override vs. Rewrite

• Override: Subclasses reimplement methods inherited from superclass.
• Override: A subclass adds or modifies functionality to an existing method of the superclass while retaining the original implementation.

Example

Suppose we have an

Animal superclass that defines a speak() method:

class Animal {
    public void speak() {
        System.out.println("Animal speaks!");
    }
}

Now we create a

Dog subclass that inherits from Animal and overrides the speak() method:

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

here In this case, the

speak() method is overridden, which means that the subclass method completely replaces the parent class method.

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