insert null values to mysql database

Question

i want to insert data to a mysql database but it is insert with null value and it is not null . i don't understand where is the error in my code . this is the page xhtml :

<div id="div1" style="height: 400px; width: 400px; margin: 0 auto; background-color: white;">
            <H4>Créer un compte</H4>
            <h:panelGrid columns="2" cellpadding="5">
            <h:outputLabel for="nom" value="Nom" style="font-weight:bold" />
            <p:inputTextarea rows="1" cols="20"  value="#{userBean.user.nom}" required="true" />
            <h:outputLabel for="prenom" value="Prenom" style="font-weight:bold" />
            <p:inputTextarea rows="1" cols="20"  value="#{userBean.user.prenom}" required="true" />
            <h:outputLabel for="adresse" value="Adresse" style="font-weight:bold" />
            <p:inputTextarea rows="1"  cols="20" value="#{userBean.user.adresse}" required="true" />
            <h:outputLabel for="email" value="Email" style="font-weight:bold" />
            <p:inputTextarea rows="1"  cols="20" value="#{userBean.user.email}" required="true" />
            <h:outputLabel for="mot" value="Mot de Passe" style="font-weight:bold" />
            <p:inputTextarea rows="1" cols="20" value="#{userBean.user.password}" required="true" />
                <f:facet name="footer">
                    <p:commandButton value="S'inscrire" immediate="true" action="#{userBean.addUtilisateur}">
                        <f:param name="ins1" value="true"></f:param>
                    </p:commandButton>
                    <h:outputLabel for="login" value="Vous possédez déjà un compte ? " />
                    <p:commandLink id="rr" immediate="true" action="#{loginBean.retourLogin}" ajax="false">
                        <h:outputText value="Connexion" />
                    </p:commandLink>
                </f:facet>
            </h:panelGrid>
        </div>

and this is the bean :

  @Named
public class UserBean implements Serializable {


    @Inject
    private UtilisateurServiceImpl utilisateurService;
    private User user = new User();

    public void addUtilisateur(){

        utilisateurService.addUtilisateur(user);
        user = new User();


    }

    public UtilisateurServiceImpl getUtilisateurService() {
        return utilisateurService;
    }

    public void setUtilisateurService(UtilisateurServiceImpl utilisateurService) {
        this.utilisateurService = utilisateurService;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

and this is the dao :

@Override
public void addUtilisateur(User utilisateur) {
    if(utilisateur!=null)
    utilisateur = this.entityManager.merge(utilisateur);
}