Static Binding and Dynamic Binding

Your example is dynamic binding, because at run time it is determined what the type of a is, and the appropriate method is called.

Now assume you have the following two methods as well:

public static void callEat(Animal animal) {
    System.out.println("Animal is eating");
}
public static void callEat(Dog dog) {
    System.out.println("Dog is eating");
}

Even if you change your main to

public static void main(String args[])
{
    Animal a = new Dog();
    callEat(a);
}

this will print Animal is eating, because the call to callEat uses static binding, and the compiler only knows that a is of type Animal.