java-core-: programming-to-an-interface

Act -oriented programming rather than facial programming is the best practice, because it improves the flexibility and scalability of the code, and follows the core principles of object -oriented programming (OOP). The following are some reasons:

1. Promote abstraction

Interface Definition Contract:
• The interface specification class should What to do instead of how to do . This abstract decoupling client code (dependence on interface) and specific implementation. For interface programming, you focus on defining behaviors rather than specific implementation.

2. Support the principle of upside -down inversion (solid principle)

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Relying on inverted principles (DIP):

High -level modules (business logic) should not depend on low -level modules (implementation); both should rely on abstraction (interface).

• For example: service can depend on the interface, not specific implementation, such as or
. This ensures flexibility and reduces coupling.
• PaymentProcessor PaymentGateway StripeGateway 3. Support polymorphism PayPalGateway

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Facing interface programming, multiple classes can achieve the same interface, so that they can be easily swapped to use them.

For example: and both realize the

interface. If your code depends on instead of specific implementation, you can switch between

and
• without modifying the code.
• ArrayList LinkedList 4. Improve code flexibility and reuse List List ArrayList LinkedList Easy to replace:
You can replace one implementation with another implementation (for example, switch from one database service to another database service) without changing the client code.

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Repeatability:

The code written for the interface can be seamlessly work with any class.

5. Simplify testing and simulation
Simulation for testing:
• The interface allows the creation of analog implementation for unit testing. For example: If you depend on the
interface, you can use simulation to perform testing instead of actual database.

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6. Facing the future

• Add new implementation is simpler because you don't need to modify the existing code. You only need to create a new class that realizes existing interfaces.
• Example DatabaseService

By facing interface programming, the

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class can work with any

implementation (, , etc.) without modification.

Key advantage review:

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Dealing code (reduced tight coupling).

// 接口
public interface Animal {
    void speak();
}

// 实现 1
public class Dog implements Animal {
    @Override
    public void speak() {
        System.out.println("Woof!");
    }
}

// 实现 2
public class Cat implements Animal {
    @Override
    public void speak() {
        System.out.println("Meow!");
    }
}

// 客户端代码
public class AnimalSound {
    public void makeAnimalSpeak(Animal animal) {
        animal.speak();
    }
}

Makes the code easier to expand and maintain.

• Simplified testing. Animal AnimalSound Encourage the principle of OOP, such as abstraction and polymorphism. Animal Dog Cat Through interface programming, you can build a system that is flexible, modular and more in line with the best practice.

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