EntityManager still null with both annotation or EntityManagerFactory method

StackOverflow https://stackoverflow.com/questions/21157948

Question

I have a Java EE project using JPA. My tables are auto-generated by hibernate when my server is starting so my entites are correct. I need now to insert / update data using an entitymanager. When I use the annotated entity manager or the standard one using the entityManagerFactory I got the NullPointer exception.

my persistence.xml :

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0"
 xmlns="http://java.sun.com/xml/ns/persistence"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
 http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">

        <persistence-unit name="LogmonPU" transaction-type="JTA">
                <provider>org.hibernate.ejb.HibernatePersistence</provider>
                <jta-data-source>java:jboss/datasources/LogmonDS</jta-data-source>
                <properties>
                        <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect" />
                        <property name="hibernate.hbm2ddl.auto" value="update" />
                        <property name="hibernate.archive.autodetection" value="class" />
                        <property name="hibernate.show_sql" value="true" />
                        <property name="hibernate.format_sql" value="true" />
                </properties>
        </persistence-unit>
</persistence>

my abstractDAO class : 

package com.st.safir.LogMonitoring.ejb;

import java.io.Serializable;
import java.util.Collection;

import javax.persistence.EntityManager;

/**
 * @author benoit brayer
 *
 * @param <E>
 *            The class entity needed to be mapped
 * @param <PK>
 *            The primary key type for this class
 */
public abstract class AbstractDAO<E
extends Serializable, PK extends Serializable> {
    /** */
    private final transient Class<E> mEntityClass;
    /**
     * @param entityClass the entity needed to be mapped by the dao class
     */
    public AbstractDAO(final Class<E> entityClass) {
        mEntityClass = entityClass;
    }

    /**
     * @return the EntityManager object corresponding to the mapped entity class
     */
    protected abstract EntityManager getEntityManager();

    /**
     * @return all objects mapped by entity
     */
    protected abstract Collection<E> getAll();

    /**
     * @param entity an instance of the entity needed to be add database
     */
    public final void create(final E entity) {
        final EntityManager entityManager = getEntityManager();
        entityManager.persist(entity);
    }

    /**
     * @param id the id of the desired entity object
     * @return the entity object matching the specified id
     */
    public final E getById(final PK id) {
        return getEntityManager().find(mEntityClass, id);
    }
}

my EJB used like my model :

package com.st.safir.LogMonitoring.ejb;

import java.util.Collection;

import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;

import com.st.safir.LogMonitoring.jpa.User;

/**
 * @author benoit brayer
 */
@Stateless(name = "userEJB")
public class UserEJB extends AbstractDAO<User, Long> {

    /** */
    @PersistenceContext(unitName = "LogmonPU")
    private EntityManager em;

    @Override
    protected EntityManager getEntityManager() {
        return em;
    }

    /** */
    public UserEJB() {
        super(User.class);
    }

    @SuppressWarnings("unchecked")
    @Override
    protected Collection<User> getAll() {
        Query query = em.createQuery("SELECT u from WEB_USER u");
        return (Collection<User>) query.getResultList();
    }

    /**
     * @param username the username matching the desired entity object
     * @return the entity object corresponding to the database row
     */
    public final User getUserByUsername(final String username) {
        Query query = em
                .createQuery("SELECT u from WEB_USER u where u.username = ?1")
                .setParameter(1, username);
        return (User) query.getSingleResult();
    }

}

Error log : 

com.sun.faces.mgbean.ManagedBeanCreationException: Cant instantiate class: com.st.safir.LogMonitoring.jsf.index.IndexBean.
    at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:193)
    at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:102)
    at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409)
    at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269)
    at com.sun.faces.el.ManagedBeanELResolver.resolveBean(ManagedBeanELResolver.java:244)
    at com.sun.faces.el.ManagedBeanELResolver.getValue(ManagedBeanELResolver.java:116)
    at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
    at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
    at org.apache.el.parser.AstIdentifier.getValue(AstIdentifier.java:72)
    at org.apache.el.parser.AstValue.getValue(AstValue.java:147)
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189)
    at com.sun.faces.facelets.el.ELText$ELTextVariable.writeText(ELText.java:227)
    at com.sun.faces.facelets.el.ELText$ELTextComposite.writeText(ELText.java:150)
    at com.sun.faces.facelets.compiler.TextInstruction.write(TextInstruction.java:85)
    at com.sun.faces.facelets.compiler.UIInstructions.encodeBegin(UIInstructions.java:82)
    at com.sun.faces.facelets.compiler.UILeaf.encodeAll(UILeaf.java:183)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:125)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:288)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:840)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:622)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:560)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:488)
    at org.apache.jasper.runtime.PageContextImpl.doForward(PageContextImpl.java:706)
    at org.apache.jasper.runtime.PageContextImpl.forward(PageContextImpl.java:677)
    at org.apache.jsp.index_jsp._jspService(index_jsp.java:64)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:326)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:253)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248)
    at com.c2alliance.commons.sso.client.filter.AllianceCASAuthorizationFilter.doFilter(AllianceCASAuthorizationFilter.java:215)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:280)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248)
    at edu.yale.its.tp.cas.client.filter.CASFilter.doFilter(CASFilter.java:473)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:280)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161)
    at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50)
    at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
    at com.st.safir.LogMonitoring.ejb.UserEJB.getUserByUsername(UserEJB.java:43)
    at com.st.safir.LogMonitoring.jsf.controller.UserControllerBean.isUserFirstLogin(UserControllerBean.java:42)
    at com.st.safir.LogMonitoring.jsf.controller.UserControllerBean.webAppUserAuthentication(UserControllerBean.java:69)
    at com.st.safir.LogMonitoring.jsf.index.IndexBean.<init>(IndexBean.java:51)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at java.lang.Class.newInstance(Unknown Source)
    at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:188)
    ... 59 more

thanks in advance. Regards

EDIT :

The controller called my my JSF managed bean dealing with business logic : package com.st.safir.LogMonitoring.jsf.controller;

import java.io.Serializable;

import javax.annotation.ManagedBean;
import javax.faces.bean.RequestScoped;

import com.st.safir.LogMonitoring.ejb.UserEJB;
import com.st.safir.LogMonitoring.jpa.User;

/**
 * @author benoit brayer
 */
@RequestScoped
@ManagedBean
public class UserControllerBean implements Serializable {

    /**
     * Generated attribute for Serialization.
     *
     * @attribute serialVersionUID serialisation id
     * @see java.io.Serializable
     */
    private static final long serialVersionUID = 1L;

    /** */
    private User mUser;

    /**
     * @return true if it is the user first login & false if the user has
     *         already an account
     * @param username
     *            the user username
     */
    public final boolean isUserFirstLogin(final String username) {
        Boolean firstLogin = true;
        UserEJB userEjb = new UserEJB();
        User user = userEjb.getUserByUsername(username);
        if (user != null) {
            firstLogin = false;
        }
        return firstLogin;
    }


    /**
     * Operations called after getting the usename
     * of the user who logged-in using SSO.
     * @param username
     *            the user username
     */
    public final void webAppUserAuthentication(final String username) {
        User user = null;
        UserEJB userEjb = new UserEJB();
        if (isUserFirstLogin(username)) {
            user = new User();
            user.setUsername(username);
            userEjb.create(user);
        } else {
            user = userEjb.getUserByUsername(username);
        }
        this.setUser(user);
    }

    .... other stuff

my indexbean managed bean of my index.xhtml page:

/** JSF Facelet
 * @author Benoit Brayer
 * @imports java.io.Serializable;
 * @imports javax.faces.bean.ManagedBean;
 * @imports javax.faces.bean.RequestScoped;
 * @import javax.faces.context.FacesContext;
 * @import javax.servlet.http.HttpServletRequest;
 */
package com.st.safir.LogMonitoring.jsf.index;

import java.io.Serializable;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.RequestScoped;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpServletRequest;

import com.st.safir.LogMonitoring.jsf.controller.UserControllerBean;

/**
 * JSF ManagedBean for index page.
 */
@RequestScoped
@ManagedBean(name = "indexBean")
public class IndexBean implements Serializable {
    /**
     * Generated attribute for Serialization.
     *
     * @attribute serialVersionUID serialisation id
     * @see java.io.Serializable
     */
    private static final long serialVersionUID = 1L;

    /**
     * Returns the name of the jsf Bean.
     */
    private String mNom = "indexBean";

    /** */
    private UserControllerBean userController = new UserControllerBean();

    /**
     * @return the name of the servlet
     */
    public final String getNom() {
        return mNom;
    }

    /** IndexBean constructor. */
    public IndexBean() {
         userController.webAppUserAuthentication((((HttpServletRequest)
         FacesContext.getCurrentInstance().getExternalContext().getRequest())
         .getUserPrincipal()).toString());
    }

    ... other stuff

I finally solve half of my problem using :

private EntityManager em = (EntityManager) Persistence
        .createEntityManagerFactory("LogmonPU")
        .createEntityManager();

instead of :

@PersistenceContext(unitName = "LogmonPU")
private EntityManager em;

In my EJB files.

Adding theses lines into my persistence.xml : 

<class>com.st.safir.LogMonitoring.jpa.User</class>

and

<property name="hibernate.transaction.factory_class"  value="org.hibernate.transaction.JDBCTransactionFactory" />
<property name="hibernate.transaction.jta.platform" value="org.hibernate.service.jta.platform.internal.JBossAppServerJtaPlatform" />

My entity manager is not more null but I still cant insert in database. No row appear in my database after this. My jboss log : 

janv./17 15:20:19,710 INFO  [stdout] (http-localhost-127.0.0.1-8080-1) Hibernate: 
janv./17 15:20:19,712 INFO  [stdout] (http-localhost-127.0.0.1-8080-1)     select
janv./17 15:20:19,715 INFO  [stdout] (http-localhost-127.0.0.1-8080-1)         S_INC_TUSER.nextval 
janv./17 15:20:19,717 INFO  [stdout] (http-localhost-127.0.0.1-8080-1)     from
janv./17 15:20:19,719 INFO  [stdout] (http-localhost-127.0.0.1-8080-1)         dual

Which is basically my sequence to ato-increment my rows using an oracle database.

Was it helpful?

Solution

SOLVING FINALLY THE PROBLEM

To solve finally the problem, I changed my persistence.xml like this : 

<persistence-unit name="LogmonPU" transaction-type="RESOURCE_LOCAL">

I also use my entity manager like this from now : 

public final User create(final User entity) {
    EntityManager entityManager = getEntityManager();
    entityManager.getTransaction().begin();
    entityManager.persist(entity);
    entityManager.getTransaction().commit();
    entityManager.close();
    return entity;
}

That was exausted but I solved it finally -.-' Thanks for the comments which helped me to sort it out.

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