A exception with : org.hibernate.MappingException: Named que

[richie-lea]

A exception with : org.hibernate.MappingException: Named query not known.
When my Servlet invoke like this:

try {
 InitialContext ctx = new InitialContext();
 log.info("InitialContext ctx = new InitialContext();");
 userFacad
 log.info("userFacade =e = (UserFacadeService) ctx.lookup("UserFacade/local"); (UserFacadeService) ctx.lookup(\"UserFacade/local\");");
 } catch (Exception e) {
 e.printStackTrace();
 log.info(e);
 }
 userFacade.regUser(new User(userName, password));

Jboss Server throw exception like that:

exception

javax.ejb.EJBTransactionRolledbackException: javax.persistence.PersistenceException: org.hibernate.MappingException: Named query not known: findUserByName
 org.jboss.ejb3.tx.Ejb3TxPolicy.handleInCallerTx(Ejb3TxPolicy.java:89)
 org.jboss.aspects.tx.TxPolicy.invokeInCallerTx(TxPolicy.java:130)
 org.jboss.aspects.tx.TxInterceptor$Required.invoke(TxInterceptor.java:196)
 org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:98)
 org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:76)
 org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:98)
 org.jboss.ejb3.stateless.StatelessInstanceInterceptor.invoke(StatelessInstanceInterceptor.java:54)
 org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:98)
 org.jboss.aspects.security.AuthenticationInterceptor.invoke(AuthenticationInterceptor.java:78)
 org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:98)
 org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:47)
 org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:98)
 org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(AsynchronousInterceptor.java:106)
 org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:98)
 org.jboss.ejb3.stateless.StatelessContainer.localInvoke(StatelessContainer.java:181)
 org.jboss.ejb3.stateless.StatelessLocalProxy.invoke(StatelessLocalProxy.java:79)
 $Proxy86.findByName(Unknown Source)
 richie.gt.ejb3.facade.UserFacade.regUser(UserFacade.java:37)

I don't know why it happened.Help~~This is UserFacade Class.

public User regUser(User user) {
 /**
 * save a new User
 */
 if (um.findByName(user.getUserName()) != null)
 return null;
 um.save(user);
 return um.findByName(user.getUserName());
 //um is a instance of UserManager class
 }

This is UserManager Class:

@NamedQueries( {
 @NamedQuery(name = "findUserByName", query = "SELECT u FROM User u WHERE u.userName = : userName")})
@Stateless
@Local( { richie.gt.ejb3.service.UserManagerService.class })
public class UserManager implements UserManagerService {

 @PersistenceContext
 protected EntityManager em;

 /**
 * findByName (Func)
 */
 public User findByName(String userName) {
 return (User) em.createNamedQuery("findUserByName").setParameter(
 "userName", userName).getSingleResult();

 }

This is persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence>
 <persistence-unit name="gt">
 <jta-data-source>java:MySqlDS</jta-data-source>
 <class>richie.gt.ejb3.manager.UserManager</class>
 <properties>
 <property name="hibernate.hbm2ddl.auto" value="create-drop" />
 <property name="show_sql">true</property>
 <property name="current_session_context_class">thread</property>
 <property name="connection.pool_size">1</property>
 </properties>
 </persistence-unit>
</persistence>

Thank you~ your attention