Why Java doesn't allow to reduce the accessibility of a method du

Question

Why Java compiler does not allow to reduce the accessibility of a method during inheritance?
( Eg; If the base class has a public method and if that method is overridden in child class but
with defuault access, it gives compile error)
Supposed answer:
Because in the runtime, it cannot check the access modifier.
Suppose A is the base class. It has a method fun() as public.
B is the derived class of A.
Suppose in some other class (say C) there is a method myFun() which takes A as parameter and
calls the fun() method of A. So that method can take B
also as parameter (As it is derived from A).
So if the fun() method's accessibility is reduced in B, whether "that can
be called in C or not" is not known. that is why compiler does not
allow the reduce the accessibility of a method during inheritance.
Member variables do not have this problem as they can be checked at
compile time.
Is this explanation correct?

Answer 1

You can give private access, sort of... you could fake it, if the goal is to prevent someone from doing what the method does. Of course, they could (as long as A isn't abstract) create their own A and do whatever they want.
class A {
   public void doThis() {
class B extends A {
   public void doThis() {
      // explicitly do nothing
}But I think generally, this shouldn't be a problem. I'm not sure if it's something that is common for creating an API to subclass another class to hide the superclass's methods. Usually you are adding functionality to a subclass that is for more specific things then the superclass supports. I mention creating an API because if it's just for some application class, then you are writing it, so use or not use the methods as you want. It's APIs for library type classes that other people would use, and if you are extending the library, and really need people not to call methods for some reason, document it. Maybe a good place for an assertion?