Andrei Karzhou [https://community.jboss.org/people/rfe.cook] created the discussion "EJB reference always null.Jboss 6" To view the discussion, visit: https://community.jboss.org/message/826801#826801 -------------------------------------------------------------- I am deleveloping web project EJB,JPA - Hibernate as provider, JBoss 6,MySql. I new in EJB, JPA.I have problems with load ejb bean in servlet. **persistence.xml** <?xml version="1.0" encoding="UTF-8"?> <persistence xmlns=" http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence" version="2.0">     <persistence-unit name="LibraryPersistenceUnit" transaction-type="JTA">         <provider>org.hibernate.ejb.HibernatePersistence</provider>         <jta-data-source>java:/MySqlDS</jta-data-source>         <class>library.entity.User</class>         <class>library.entity.Book</class>         <properties>             <property name="hibernate.show_sql" value="true" />             <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>         </properties>     </persistence-unit> </persistence> **UserFacade.java**     @Local     public interface UserFacade {         User findUserByLoginAndPassword(String login, String password);        /* List<User> getClients();         void returnBooks(long userId, long[] ids);         void takeBooks(long userId, long[] ids);*/     } **UserFacadeImpl.java**     package library.facades.impl;     import library.dao.impl.UserDAO;     import library.entity.User;     import library.facades.interfaces.UserFacade;     import javax.ejb.EJB;     import javax.ejb.Stateless;     @Stateless     public class UserFacadeImpl implements UserFacade {         @EJB         private UserDAO userDAO;         public UserFacadeImpl() {         }         public User findUserByLoginAndPassword(String login, String password) {             User user = userDAO.selectUserByLoginAndPassword(login, password);             return user;         }      /*   public List<User> getListClients() {             List<User> userList = userDAO.getClients();             return userList;         }         public void returnBooks(long userId, long[] ids) {             userDAO.returnBooks(userId, ids);         }         public void takeBooks(long userId, long[] ids) {             userDAO.takeBooks(userId, ids);         }*/     } **UserDAO.java**     package library.dao.impl;     import library.dao.interfaces.GenericDAO;     import library.entity.User;     import javax.ejb.Local;     import javax.ejb.Stateless;     import java.util.HashMap;     import java.util.Map;     @Stateless     public class UserDAO extends GenericDAO {         public UserDAO() {             super(User.class);         }         public User selectUserByLoginAndPassword(String login, String password) {             Map<String, Object> parameters = new HashMap<String, Object>();             parameters.put("login", login);             parameters.put("password", password);             return (User) super.findOneResult(User.SELECT_USER_BY_LOGIN_AND_PASSWORD, parameters);         }         /*public List<User> getClients() {             Query namedQuery = entityManager.createNamedQuery(User.ALL_CLIENTS, User.class);             List<User> clientsList = namedQuery.getResultList();             return clientsList;         }         @Override         public void returnBooks(long userId, long[] ids) {             User user = entityManager.find(User.class, userId);             for (long id : ids) {                 Book book = entityManager.find(Book.class, id);                 user.getTakenBooks().remove(book);             }             entityManager.merge(user);         }         @Override         public void takeBooks(long userId, long[] ids) {             User user = entityManager.find(User.class, userId);             for (long id : ids) {                 Book book = entityManager.find(Book.class, id);                 user.getTakenBooks().add(book);             }             entityManager.merge(user);         }*/     } **GenericDAO.java**     package library.dao.interfaces;     import javax.persistence.EntityManager;     import javax.persistence.PersistenceContext;     import javax.persistence.Query;     import java.util.List;     import java.util.Map;     public abstract class GenericDAO<T> {         private static final String LIBRARY_PERSISTENCE_UNIT = "LibraryPersistenceUnit";         @PersistenceContext(unitName = LIBRARY_PERSISTENCE_UNIT)         private EntityManager entityManager;         private Class<T> entityClass;         public GenericDAO() {         }         public GenericDAO(Class<T> entityClass) {             this.entityClass = entityClass;         }         public void save(T entity) {             entityManager.persist(entity);         }         protected void delete(Object id, Class<T> classe) {             T entityToBeRemoved = entityManager.getReference(classe, id);             entityManager.remove(entityToBeRemoved);         }         public T update(T entity) {             return entityManager.merge(entity);         }         public T find(int entityID) {             return entityManager.find(entityClass, entityID);         }         // Using the unchecked because JPA does not have a         // entityManager.getCriteriaBuilder().createQuery()<T> method         @SuppressWarnings({"unchecked", "rawtypes"})         public List<T> findAll() {            /* CriteriaQuery cq = entityManager.getCriteriaBuilder().createQuery();             cq.select(cq.from(entityClass));*/             return null;//entityManager.createQuery(cq).getResultList();         }         // Using the unchecked because JPA does not have a         // ery.getSingleResult()<T> method         @SuppressWarnings("unchecked")         protected T findOneResult(String namedQuery, Map<String, Object> parameters) {             T result = null;             try {                 Query query = entityManager.createNamedQuery(namedQuery);                 // Method that will populate parameters if they are passed not null and empty                 if (parameters != null && !parameters.isEmpty()) {                     populateQueryParameters(query, parameters);                 }                 result = (T) query.getSingleResult();             } catch (Exception e) {                 System.out.println("Error while running query: " + e.getMessage());                 e.printStackTrace();             }             return result;         }         private void populateQueryParameters(Query query, Map<String, Object> parameters) {             for (Map.Entry<String, Object> entry : parameters.entrySet()) {                 query.setParameter(entry.getKey(), entry.getValue());             }         }         public EntityManager getEntityManager() {             return entityManager;         }         public void setEntityManager(EntityManager entityManager) {             this.entityManager = entityManager;         }     } **LibraryController**     package library.controller;     import library.entity.User;     import library.facades.interfaces.UserFacade;     import library.resourses.constants.Constants;     import library.resourses.enums.Role;     import javax.ejb.EJB;     import javax.servlet.RequestDispatcher;     import javax.servlet.ServletException;     import javax.servlet.http.HttpServlet;     import javax.servlet.http.HttpServletRequest;     import javax.servlet.http.HttpServletResponse;     import java.io.IOException;     public class LibraryController extends HttpServlet {         @EJB         private UserFacade userFacade;         protected void doPost(HttpServletRequest request, HttpServletResponse response) throws javax.servlet.ServletException, IOException {             performAction(request, response);         }         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws javax.servlet.ServletException, IOException {             performAction(request, response);         }         private void performAction(HttpServletRequest request, HttpServletResponse response) {             String pageType = request.getParameter(Constants.PAGE_TYPE);             if (pageType != null) {                 try {                     String page = null;                     String login = request.getParameter(Constants.USER_LOGIN);                     String password = request.getParameter(Constants.USER_PASSWORD);                     User user = userFacade.findUserByLoginAndPassword(login, password);                     if (user == null) {                         request.getSession().setAttribute(Constants.ERROR,                                 Constants.ERROR_MESSAGE_7);                         page = Constants.MAIN_PAGE;                     } else {                         String namePage = user.getRole().toString().toLowerCase();                         if (isClient(user)) {                             request.getSession().setAttribute(Constants.CLIENT,                                     user);                             request.getSession().setAttribute(Constants.ERROR, null);                         } else if (isAdministrator(user)) {                             request.getSession().setAttribute(Constants.ADMINISTRATOR,                                     user);                             request.getSession().setAttribute(Constants.ERROR, null);                         }                         page = Constants.START_PAGES + namePage + Constants.END_PAGES;                     }                     RequestDispatcher requestDispatcher = getServletContext().getRequestDispatcher(page);                     requestDispatcher.forward(request, response);                 } catch (ServletException e) {                     e.printStackTrace();                 } catch (IOException e) {                     e.printStackTrace();                 }             }         }         private boolean isAdministrator(User user) {             return user.getRole().equals(Role.ADMINISTRATOR);         }         private boolean isClient(User user) {             return user.getRole().equals(Role.CLIENT);         }     } I get null for userFacade.Can you explain me what I do wrong. Thanks. -------------------------------------------------------------- Reply to this message by going to Community [https://community.jboss.org/message/826801#826801] Start a new discussion in EJB3 Development at Community [https://community.jboss.org/choose-container!input.jspa?contentType=1&...]