class Human {
    private final String name;
    private final Heart heart;

    public Human(String name) {
        this.name = name;
        this.heart = new Heart();   // Composition: Human creates Heart
    }

    public Heart getHeart() {
        return heart;
    }

    public String getName() {
        return name;
    }
}

class Heart {

    public void beat() {
        System.out.println("Heart is beating...");
    }
}

public class Example01 {
    public static void main(String[] args) {

        // --- Create a Human (automatically creates a Heart) ---
        Human human = new Human("Ahmed");

        System.out.println(human.getName() + " is alive.");
        human.getHeart().beat();

        // In code: if we set the reference to null, the Heart becomes unreachable.
        human = null;

        System.out.println("Human object reference removed. "
                + "Heart no longer exists independently.");
    }
}