What is the inheritance mechanism of classes in java

Class inheritance in Java allows subclasses to inherit properties and methods from parent classes, providing single-root inheritance, multiple implementations, method overriding and overloading. Benefits include code reuse, polymorphism, and code extensions.

Class inheritance mechanism in Java

Inheritance in Java is a basic concept of object-oriented programming. Allows one class (subclass) to inherit properties and methods from another class (parent class).

Creation of subclasses

To create a subclass, you can use the following syntax:

class 子类 extends 父类 {
    // 子类的代码
}

For example:

class Animal {
    protected String name;
}

class Dog extends Animal {
    public void bark() {
        System.out.println("汪汪!");
    }
}

In In the above example, the Dog class inherits the name variable from the Animal class. In addition, the Dog class also defines its own bark() method.

Characteristics of inheritance

Inheritance in Java has the following characteristics:

• Single root inheritance:Every child A class can only have one parent class.
• Multiple implementations: A class can implement multiple interfaces.
• Method rewriting: Subclasses can override existing methods in the parent class to provide specific implementations.
• Method overloading: Subclasses can add new methods or overload methods in the parent class with different parameter lists.
• Method access: Subclasses can access methods marked public and protected in the parent class, but cannot access methods marked private method.

Overriding and rewriting

• Overriding: The methods declared in the subclass are the same as those declared in the parent class methods have the same name, parameter list, and return type.
• Overloading: The method declared in the subclass has the same name as the method declared in the parent class, but the parameter list or return type is different.

Benefits

The inheritance mechanism provides the following benefits:

• Code reuse: Subclasses can Inherit the properties and methods of the parent class without rewriting the code.
• Polymorphism: Objects of subclasses can be used in the context of parent class objects, thus improving code flexibility.
• Code extension: Subclasses can extend the functionality of parent classes to provide new features for applications.

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