How to implement interfaces and abstract classes in Java

The difference between the implementation of interfaces and abstract classes in Java is: interface: provides a collection of abstract methods, and the class implements the methods in the interface; abstract class: provides partial method implementation, and the class inherits the abstract class to obtain partial implementation; the interface can only define method signatures , cannot contain implementation; abstract classes can contain abstract methods and non-abstract methods; classes inherit methods in interfaces by implementing interfaces; classes obtain partial implementation provided by abstract classes by inheriting abstract classes.

Implementation of interfaces and abstract classes in Java

Interface (Interface)

• Interface is A set of abstract methods that defines the methods that a class must implement.
• The interface cannot contain any method implementation, only method declaration.
• A class can inherit the methods in the interface by implementing the interface.

Implementation interface:

public class Vehicle implements Drivable {

    public void drive() {
        // 驾驶车辆的实现
    }
}

Abstract Class (Abstract Class)

• Abstract class is an A class that provides partial method implementation.
• Abstract classes can contain abstract methods and non-abstract methods.
• A class can obtain part of the implementation provided by the abstract class by inheriting the abstract class.

Implement abstract class:

public class Car extends Vehicle {

    @Override
    public void drive() {
        super.drive();
        // 其他特定的驾驶车辆实现
    }
}

Practical case:

Create an interface and abstract class :

interface Drivable {
    void drive();
}

abstract class Vehicle {
    public abstract void drive();

    public void start() {
        // 公共方法的实现
    }
}

Create a class that implements the interface:

public class Bike implements Drivable {

    @Override
    public void drive() {
        // 驾驶自行车
    }
}

Create a class that inherits the abstract class:

public class Truck extends Vehicle {

    @Override
    public void drive() {
        // 驾驶卡车
    }
}

Usage:

Drivable bike = new Bike();
bike.drive();

Vehicle truck = new Truck();
truck.drive();
truck.start();

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