How to Implement C++-Style Protected Members in Java?

How can I implement C++-style protected members in Java?

class Parent {
    protected int protectedVar;
    public Parent() {
        protectedVar = 5;
    }
}

class Child extends Parent {
    public void display() {
        System.out.println("Protected Variable: " + protectedVar);
    }
}

In Java, the concept of protected members is similar to that of C++; however, there are key differences in their implementations due to the nature of the languages. This guide will help you understand how protected members work in Java and how they can be effectively utilized in your object-oriented programming endeavors.

class Animal {
    protected String name;
    public Animal(String name) {
        this.name = name;
    }
}

class Dog extends Animal {
    public void bark() {
        System.out.println(name + " says Woof!");
    }
}

Causes

• The protected access modifier allows visibility to the class itself, its subclasses, and classes in the same package, making inheritance easier.
• Java does not have a direct equivalent to C++'s protected members that are limited to the class hierarchy alone.

Solutions

• Declare class members as protected to allow access in subclasses and classes within the same package.
• Use inheritance and polymorphism to extend class functionality while maintaining access to protected variables.

Mistake: Forgetting that protected variables are accessible to classes in the same package only.

Solution: Use package-private access if you want to restrict access solely to classes in the same package.

Mistake: Confusing the visibility of protected members with private members.

Solution: Remember that private members are hidden from subclasses, while protected members are accessible to subclasses.