Change the access modifier of an overridden method in Java?

Question

Is there a reason one can change the access modifier of an overridden method? For instance,

abstract class Foo{
    void start(){...}
}

And

Answer 1

The explaination is this:-

It's a fundamental principle in OOP: the child class is a fully-fledged instance of the >parent class, and must therefore present at least the same interface as the parent class. >Making protected/public things less visible would violate this idea; you could make child >classes unusable as instances of the parent class.

 class Person{
 public void display(){
  //some operation
 }
 }

class Employee extends Person{
private void display(){
   //some operation
 }


 Person p=new Employee();

Here p is the object reference with type Person(super class),when we are calling >p.display() as the access modifier is more restrictive the object reference p cannot access child object of type Employee