extends 및 super

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extends 사용하기

생성자에서 super(...) 사용하기

super.method()

언제 사용할까요?

코드: extends와 super

public class Main {
  // Base class with a simple constructor and method
  static class Vehicle {
    String brand;
    Vehicle(String brand) {
      this.brand = brand; // parent sets its own field
    }
    void printInfo() {
      System.out.println("Vehicle brand: " + brand);
    }
  }

  // Subclass reuses Vehicle with extends
  static class Car extends Vehicle {
    int doors;
    Car(String brand, int doors) {
      super(brand);    // call parent constructor first
      this.doors = doors;
    }
    void printInfo() {
      // Add extra info, but reuse parent behavior
      super.printInfo(); // call parent method
      System.out.println("Doors: " + doors);
    }
  }

  public static void main(String[] args) {
    // Create a Car (which is a Vehicle)
    Car c = new Car("EcoMotors", 4);
    c.printInfo(); // shows parent info then child info
  }
}

super(...) 확인

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