Question

Is it possible to a class has a method that can only be called by it’s objects and hidden for a subclass object? For instance:

class ClassOne {
    ... // attributes

    public void doSomething() { ... }
}

class ClassTwo extends ClassOne {
    ... // attributes and methods
}

ClassOne c1 = new ClassOne();
c1.doSomething(); // ok to call

ClassTwo c2 = new ClassTwo();
c2.doSomething(); // forbidden

I know this seems weird thinking in therms of inheritance, but is it possible?

PS: the objective of this question is just to learn more about inheritance of OO programming.

Answer 1

It’s not possible and your right that this would break inheritance. Think about

ClassOne c2 = new ClassTwo();
c2.doSomething(); // what to do?

This has to work because ClassTwo is a ClassOne. Edit: at least is has to compile, if the method is overridden and does something else is up to your design. But you cannot make the compiler produce an error on this.