Protected class in java

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Yes, we can declare a class as protected but these classes can be only inner or nested classes. We can’t a top-level class as protected because declaring top class as protected will mean that it is accessible to the current package as well as sub packages. Now there’s no concept of sub packages in Java.
Example 1 with non inner class:

protected class Main
{
	public static void main(String[] args) {
		System.out.println("Inside protected class");
	}
}

Output:

Main.java:8: error: modifier protected not allowed here
protected class Main
          ^
1 error

Example 2 with non inner class:

protected class Show{
        void display(){
            System.out.println("Inside display method.");
        }
}
public class Main
{
	public static void main(String[] args) {
		Show show = new Show();
		show.display();
	}
}

Output:

Main.java:1: error: modifier protected not allowed here
protected class Show{
          ^
1 error

Example with inner class:

class Display {
 
   //Private nested or inner class 
   protected class InnerDisplay {
      public void display() {
         System.out.println("Protected inner class method called");
      }
   }
 
   void display() {
      System.out.println("Outer class (Display) method called");
      // Access the protected inner class
      InnerDisplay innerDisplay = new InnerDisplay();
      innerDisplay.display();
   }
}
 
public class Main {
 
   public static void main(String args[]) {
      // Create object of the outer class (Display)
      Display object = new Display();
 
      // method invocation
      object.display();
   }
}

Output:

Outer class (Display) method called 
Protected inner class method called

Java interview questions on access modifiers