How to Use Private Variables in Inherited Classes in Java?

How can I use private variables in an inherited class in Java?

class Parent {
    private int privateVar = 10;

    protected int getPrivateVar() {
        return privateVar;
    }
}

class Child extends Parent {
    public void displayPrivateVar() {
        // cannot access privateVar directly
        System.out.println("Private Variable: " + getPrivateVar()); // Accessing via protected method
    }
}

In Java, private variables in a parent class are not accessible directly from its child classes. However, you can utilize accessors like protected methods to interact with private data safely.

class Parent {
    private int privateVar = 10;

    protected int getPrivateVar() {
        return privateVar;
    }
}

class Child extends Parent {
    public void showVar() {
        // Accessing via getter method
        int value = getPrivateVar();
        System.out.println("Value from Parent: " + value);
    }
}

Causes

• Private variables are designed to encapsulate class data, maintaining control and security.
• Direct access to private members is forbidden in subclasses to promote encapsulation.

Solutions

• Use protected or public getters/setters to access private variables from a subclass.
• Change the access level of the variable to protected if needed, allowing access from subclasses.

Mistake: Trying to access a private variable directly from a child class.

Solution: Instead, use a protected or public accessor method to retrieve the private data.

Mistake: Not utilizing encapsulation principles by exposing private data through public methods.

Solution: Always keep private members encapsulated and expose only necessary data through well-defined interfaces.