How to Access a Protected Inner Class While Inheriting in Java?

How can I access a protected inner class while inheriting from it in Java?

class Outer {
    protected class Inner {
        void display() {
            System.out.println("Inner class method");
        }
    }
}

class SubClass extends Outer {
    void accessInner() {
        Inner inner = new Inner();
        inner.display();
    }
}

In Java, access to protected inner classes depends on how they are used and where the access is being requested from. When you inherit from an outer class that contains a protected inner class, you can access this inner class directly through the subclass. Here is a detailed explanation of how this works.

class Outer {
    protected class Inner {
        void show() {
            System.out.println("Hello from Inner Class");
        }
    }
}

class SubClass extends Outer {
    public void accessInnerClass() {
        Inner inner = new Inner();
        inner.show();  // Accessing the protected inner class
    }
}

Causes

• The inner class is declared as protected within an outer class.
• Inheritance allows a subclass to access protected members of its superclass including inner classes.

Solutions

• Ensure the subclass is in the same package as the outer class if not extending.
• Instantiate the protected inner class inside a method of the subclass and access its methods.

Mistake: Trying to access inner class directly without subclass instantiation.

Solution: Make sure to create an instance of the outer class or use subclass methods to access the inner class.

Mistake: Assuming inner classes are public or accessible without inheritance.

Solution: Remember that only protected members are accessible through subclasses or the same package.