interface ABC {
public void callme();
}

abstract class A implements ABC {
abstract public void callme();



void callmetoo() {
System.out.println("This is a concrete method.");
}
}

class B extends A {
public void callme() {
System.out.println("B's implementation of callme.");
}
}

class AbstractDemo {
public static void main(String args[]) {
B b = new B();
b.callme();
b.callmetoo();
}
}

//OUTPUT:
//B's implementation of callme.
//This is a concrete method.