Avoid overlapping call on Child classes

I have one base class and two child classes.

public class A {
    ........
    ........

    void func() {
        ......
        ......
    }
}

public class B extends A {
    ........
    ........

    @Override
    void func() {
        super.func();
        // other stuff
    }
}

public class C extends A {
    ........
    ........

    @Override
    void func() {
        super.func();
        // other stuff
    }
}

Now, when I am calling like this:

A b = new B();
b.func();
A c = new C();
c.func();

Now super.func() is the overlapping portion and get called two times. What's the best practices to avoid this overlapping call? How the design is supposed to be?