Java Protected

Java protected

Created By: chatGPT

Java's protected keyword is an access modifier that allows a member (variable or method) to be accessible within its own package and by subclasses. This is particularly useful in object-oriented programming, where we want to encapsulate the data while still allowing certain classes to access it.

class Animal {
    protected String sound;

    protected void makeSound() {
        System.out.println(sound);
    }
}

class Dog extends Animal {
    public Dog() {
        sound = "Bark";
    }
    
    public void bark() {
        makeSound(); // Accessing protected method
    }
}

public class Main {
    public static void main(String[] args) {
        Dog dog = new Dog();
        dog.bark(); // Outputs: Bark
    }
}

In the example above, the Animal class has a protected variable sound and a protected method makeSound(). The Dog class, which is a subclass of Animal, can access both of these members. This access control is beneficial when we want to ensure that only related classes can access certain properties and behaviors.

class Cat extends Animal {
    public Cat() {
        sound = "Meow";
    }
    
    public void meow() {
        makeSound(); // Accessing protected method
    }
}

public class Main {
    public static void main(String[] args) {
        Cat cat = new Cat();
        cat.meow(); // Outputs: Meow
    }
}

When designing your class structure, remember that using protected is a balance between accessibility and encapsulation. It allows controlled access to sensitive parts of your class hierarchy, providing a level of safety while still being flexible.

class Base {
    protected int value;

    protected Base(int value) {
        this.value = value;
    }
}

class Derived extends Base {
    public Derived(int value) {
        super(value);
    }

    public void display() {
        System.out.println("Value: " + value);
    }
}

public class Main {
    public static void main(String[] args) {
        Derived obj = new Derived(10);
        obj.display(); // Outputs: Value: 10
    }
}