Cannot reduce the visibility of the inherited method from runnable

You cannot reduce the visibility of a inherited method. Here parent class has func() method which is public and overridden by the subclass TestClass which is private. Now the compiler throws the error that I cannot the reduce the visibility.

First, when you override methods in a subclass, the overriding method must be at least as visible as the overridden method. While it is possible to take a private method and override it with a public method in a subclass, the reverse is not possible; you can't override a public method with a private method.

The ability of a subclass to override a method allows a class to inherit from a superclass whose behavior is "close enough" and then to modify behavior as needed. The overriding method has the same name, number and type of parameters, and return type as the method that it overrides.