Probleme attribut

public class Client {
	
	private String nom, prenom;
	private Commande commande;

	public Client(String prenom, String nom) {
		this.prenom = prenom;
		this.nom = nom;
	}
	
	public void enregistrerCommande(Commande commande) {
		this.commande = commande;
	}
	
	public Commande getCommande() {
		return this.commande;
	}

public class Test {
	public static void main(String[] args) {
		Client client = new Client("Robert", "Michel");
		Commande commande = new Commande(2, LocalDateTime.now());
		client.enregistrerCommande(commande);
		System.out.println(client.getCommande().getNumero());
	}