I m Beginner in Java, so someone please say how to call methodA() in Animal Through Mammal object.i cant understand why we need Downcasting and Upcasting clearly. 

```
class Animal{
void methodA(){
    System.out.println("I m Animal");
}
}
class Mammal extends Animal{
    void methodA(){
        System.out.println("I m Mammal child class of Animal");
    }
    void methodAB(){
        System.out.println("Two child class Dog and Cat I have");
    }
}

public class UpDownCast {

public static void main(String[] args) {

Animal a = new Animal();
a.methodA();

Mammal m = new Mammal();
m.methodA();

Animal A = new Mammal();
if (A instanceof Mammal){
    A.methodA();
}
Animal A1= new Animal();
Mammal M1 =(Mammal)A1;
M1.methodA();

}
}

```

Thanks in Advance.