Java における動的ポリモーフィズムと静的ポリモーフィズムの違いは何ですか?

<code class="java">class Animal {
    public void move() {
        System.out.println("Animals can move");
    }
}

class Dog extends Animal {
    @Override
    public void move() {
        System.out.println("Dogs can walk and run");
    }
}

public class Main {
    public static void main(String[] args) {
        Animal animal = new Animal(); // Animal reference and object
        Animal dog = new Dog(); // Animal reference but Dog object

        animal.move(); // Output: Animals can move
        dog.move(); // Output: Dogs can walk and run
    }
}</code>

<code class="java">class Calculation {
    void sum(int a, int b) {
        System.out.println(a + b);
    }

    void sum(int a, int b, int c) {
        System.out.println(a + b + c);
    }

    public static void main(String[] args) {
        Calculation calculation = new Calculation();
        calculation.sum(10, 10, 10); // Output: 30
        calculation.sum(20, 20); // Output: 40
    }
}</code>