# Simplest Possible JSF 2 / EJB 3.1 / JPA Component - With WAR Deployment

The welcome.xhtml page uses facelets templating mechanism. It mainly consists of a textbox and a button:         <ui:define name="body">                <h:form>                    <h:outputLabel value="Message:"/><h:inputText value="#{messageview.message.message}"/>                    <h:commandButton action="#{messageview.save}" value="Save"/>                </h:form>            </ui:define> The InputText and the Button are value-bound to a @ManagedBean with the name MessageView:@ManagedBean(name="messageview")@RequestScopedpublic class MessageView {    @EJB    MessageService messageService;    private HelloMessage message;    public MessageView() {        this.message = new HelloMessage();    }    public HelloMessage getMessage() {        return message;    }    public int getNumberOfMessages(){        return messageService.getMessages().size();    }    public String save(){        this.messageService.save(message);        return "theend";    }}The method save() returns "theend" String. This is the name of the next view. No page flow definitions in faces-config.xml are required. The MessageView managed bean instantiates and directly exposes the HelloMessage entity:@Entity@NamedQuery(name=HelloMessage.findAll,query="SELECT hm from HelloMessage hm")public class HelloMessage{    public final static String findAll = "com.abien.leancomp.business.message.entity.HelloMessage.findAll";    @Id    @GeneratedValue(strategy = GenerationType.AUTO)    private Long id;    private String message;    public HelloMessage() {    }    public String getMessage() {        return message;    }    public void setMessage(String message) {        this.message = message;    }}The actual business logic is implemented in a @Stateless no-interface view EJB 3.1: @Statelesspublic class MessageService {    @PersistenceContext    EntityManager em;    public void save(HelloMessage hm){        this.em.persist(hm);    }    public List<HelloMessage> getMessages(){        return this.em.createNamedQuery(HelloMessage.findAll).getResultList();    }}The MessageService manages the EntityManager and cares about transactions. Interestingly: the overall amount of code can be reduced with the introduction of a single EJB 3.1. You can use JSF 2 without EJBs, but then you will have to manage the persistence and transactions manually - what will result in significantly more code. You could expose the same EJB 3.1 as a RESTful service. The whole example (LeanJSF2EJB31Component) was checked-in into: http://kenai.com/projects/javaee-patterns/. It was developed with Netbeans 6.8m1 and deployed to Glassfishv3b57.Btw. the slowest "deployment" (with creation of the table) was: INFO: Deployment of LeanJSF2EJB31Component done is 895 ms[The whole book "Real World Java EE Patterns - Rethinking Best Practices"
describes lean Java EE architectures and patterns. See ServiceFacade,
Service, PDO patterns and the chapter 6 "Pragmatic Java EE
Architectures", Page 253]