OOP(object-oriented programming)

OOP core = Encapsulation + Inheritance + Polymorphism

1. Encapsulation封装

Hide internal details, expose only what’s needed.

classUser {
privateStringname;

publicStringgetName() {
returnname;
    }
}

2. Inheritance继承

Reuse and extend behavior.

classAnimal {}
classDogextendsAnimal {}

3. Polymorphism多态

Same interface, different behavior.

Animala=newDog();