form with fieldgroup and jpacontainer

hay,
i’m trying to create a form by using the bind-method of FieldGroup, so i have followed an example made by vaadin “Creating a master-details view for editing persons”

this is my class addform that i use to create the form :

public class AddActe extends HibernateCustomComponent{
	
	FormLayout form = new FormLayout();
    private Button save;
    private FieldGroup fieldGroup;
	
	public AddActe(){

	TextField acteField = new TextField("Acte");
	form.addComponent(acteField);
	TextField periodeField = new TextField("Durée");
	form.addComponent(periodeField);
	
	// Now create the binder and bind the fields
	fieldGroup = new BeanFieldGroup<Acte>(Acte.class);
	fieldGroup.setBuffered(true);
	final BeanItem<Acte> item =
			 new BeanItem<Acte>(new Acte());
	fieldGroup.setItemDataSource(item);
	fieldGroup.bind(acteField,  "libelle");
	fieldGroup.bind(periodeField, "dureeTheorique");
	
	 save = new Button("Save");
	 save.addClickListener(new Button.ClickListener(){

		@Override
		public void buttonClick(ClickEvent event) {
			
			try {
	                fieldGroup.commit();
	                editActe(null);
	            } catch (FieldGroup.CommitException e) {
	                e.printStackTrace();
	            }
			
		}});
	 
	form.addComponent(save);
	setCompositionRoot(form);
	}

	private void editActe(Acte acte) {
	    if (acte == null) {
	        acte = new Acte();
	    }
	final BeanItem<Acte> item =
	 new BeanItem<Acte>(new Acte());
	 fieldGroup.setItemDataSource(item);
	}
	}

and this is the bean that i use it to test my form i use jpacontainer to ganerate it from mysql database:

/**
 * Définition de la table Acte
 */
@Entity (name="Acte")
public class Acte implements IBase
{
	@Id
	@GeneratedValue
	@Column
	private Integer id;
	
	@Column(unique = true)
	@NotNull
	private String libelle;
    
	@Column
	private Integer dureeTheorique;
    
	@ManyToOne
	@JoinColumn(name="TypeActe_id", referencedColumnName="id")
	private TypeActe typeActe;
	
	@ManyToOne
    @JoinColumn(name="CategorieActe_id", referencedColumnName="id")
	private CategorieActe categorieActe;

	public Acte(String libelle, Integer dureeTheorique, TypeActe typeActe, CategorieActe categorieActe) {
		super();
		this.libelle = libelle;
		this.dureeTheorique = dureeTheorique;
		this.typeActe = typeActe;
		this.categorieActe = categorieActe;
	}

	public Acte() {
		super();
	}

	public Integer getId() {
		return id;
	}

	public String getLibelle() {
		return libelle;
	}

	public void setLibelle(String libelle) {
		this.libelle = libelle;
	}

	public Integer getDureeTheorique() {
		return dureeTheorique;
	}

	public void setDureeTheorique(Integer dureeTheorique) {
		this.dureeTheorique = dureeTheorique;
	}

	public TypeActe getTypeActe() {
		return typeActe;
	}

	public void setTypeActe(TypeActe typeActe) {
		this.typeActe = typeActe;
	}

	public CategorieActe getCategorieActe() {
		return categorieActe;
	}

	public void setCategorieActe(CategorieActe categorieActe) {
		this.categorieActe = categorieActe;
	}
}

The pronblem is that i don’t know how to persit data object to my filedGroup to store information entered by the form into mysql database
could you please suggest any solution could help me.
thank you