[darkapple]

As i’m beginner to hibernate, i followed a tutorial and went through the hibernate myeclipse tutorial.

I’ve created a web project and for hibernate configuration testing i’ve created a java class but i’m getting this error contineously. Here is error message and log infos copied from console.

0    [main] INFO  org.hibernate.cfg.Environment  - Hibernate 3.1.3
0    [main] INFO  org.hibernate.cfg.Environment  - hibernate.properties not found
0    [main] INFO  org.hibernate.cfg.Environment  - using CGLIB reflection optimizer
0    [main] INFO  org.hibernate.cfg.Environment  - using JDK 1.4 java.sql.Timestamp handling
93   [main] INFO  org.hibernate.cfg.Configuration  - configuring from resource: /hibernate.cfg.xml
93   [main] INFO  org.hibernate.cfg.Configuration  - Configuration resource: /hibernate.cfg.xml
390  [main] INFO  org.hibernate.cfg.Configuration  - Reading mappings from resource: com/library/Book.hbm.xml
515  [main] INFO  org.hibernate.cfg.HbmBinder  - Mapping class: com.library.Book -> book
531  [main] INFO  org.hibernate.cfg.Configuration  - Reading mappings from resource: com/library/Customer.hbm.xml
578  [main] INFO  org.hibernate.cfg.HbmBinder  - Mapping class: com.library.Customer -> customer
578  [main] INFO  org.hibernate.cfg.Configuration  - Configured SessionFactory: null
%%%% Error Creating SessionFactory %%%%
org.hibernate.MappingException: Association references unmapped class: Book
    at org.hibernate.cfg.HbmBinder.bindCollectionSecondPass(HbmBinder.java:2344)
    at org.hibernate.cfg.HbmBinder$CollectionSecondPass.secondPass(HbmBinder.java:2618)
    at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:35)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1012)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1168)
    at com.library.HibernateSessionFactory.<clinit>(HibernateSessionFactory.java:34)
    at com.library.test.LibraryTest.setUp(LibraryTest.java:70)
    at com.library.test.LibraryTest.main(LibraryTest.java:27)
593  [main] INFO  org.hibernate.cfg.Configuration  - configuring from resource: /hibernate.cfg.xml
593  [main] INFO  org.hibernate.cfg.Configuration  - Configuration resource: /hibernate.cfg.xml
593  [main] INFO  org.hibernate.cfg.Configuration  - Reading mappings from resource: com/library/Book.hbm.xml
640  [main] INFO  org.hibernate.cfg.Mappings  - duplicate import: com.library.Book->com.library.Book
640  [main] INFO  org.hibernate.cfg.Mappings  - duplicate import: com.library.Book->Book
640  [main] INFO  org.hibernate.cfg.HbmBinder  - Mapping class: com.library.Book -> book
%%%% Error Creating SessionFactory %%%%
org.hibernate.MappingException: Could not read mappings from resource: com/library/Book.hbm.xml
    at org.hibernate.cfg.Configuration.addResource(Configuration.java:485)
    at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1465)
    at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1433)
    at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1414)
    at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1390)
    at org.hibernate.cfg.Configuration.configure(Configuration.java:1310)
    at com.library.HibernateSessionFactory.rebuildSessionFactory(HibernateSessionFactory.java:86)
    at com.library.HibernateSessionFactory.getSession(HibernateSessionFactory.java:56)
    at com.library.test.LibraryTest.setUp(LibraryTest.java:70)
    at com.library.test.LibraryTest.main(LibraryTest.java:27)
Caused by: org.hibernate.DuplicateMappingException: Duplicate class/entity mapping com.library.Book
    at org.hibernate.cfg.Mappings.addClass(Mappings.java:118)
    at org.hibernate.cfg.HbmBinder.bindRoot(HbmBinder.java:154)
    at org.hibernate.cfg.Configuration.add(Configuration.java:386)
    at org.hibernate.cfg.Configuration.addInputStream(Configuration.java:427)
    at org.hibernate.cfg.Configuration.addResource(Configuration.java:482)
    ... 9 more
Exception in thread "main" java.lang.NullPointerException
    at com.library.test.LibraryTest.testAndCreateDomains(LibraryTest.java:40)
    at com.library.test.LibraryTest.main(LibraryTest.java:35)

Here is my HibernateSessionFactory class:

package com.library;


import java.io.File;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.cfg.Configuration;

/**
 * Configures and provides access to Hibernate sessions, tied to the
 * current thread of execution.  Follows the Thread Local Session
 * pattern, see {@link http://hibernate.org/42.html }.
 */
public class HibernateSessionFactory {

    /**
     * Location of hibernate.cfg.xml file.
     * Location should be on the classpath as Hibernate uses 
     * #resourceAsStream style lookup for its configuration file.
     * The default classpath location of the hibernate config file is
     * in the default package. Use #setConfigFile() to update
     * the location of the configuration file for the current session.   
     */
    private static String CONFIG_FILE_LOCATION = "/hibernate.cfg.xml";
    private static final ThreadLocal threadLocal = new ThreadLocal();
    private static Configuration configuration = new Configuration();
    private static org.hibernate.SessionFactory sessionFactory;
    private static String configFile = CONFIG_FILE_LOCATION;

    static {
       try {
         configuration.configure(configFile);
         sessionFactory = configuration.buildSessionFactory();
      } catch (Exception e) {
         System.err
               .println("%%%% Error Creating SessionFactory %%%%");
         e.printStackTrace();
      }
    }
    private HibernateSessionFactory() {
    }
   
   /**
     * Returns the ThreadLocal Session instance.  Lazy initialize
     * the <code>SessionFactory</code> if needed.
     *
     *  @return Session
     *  @throws HibernateException
     */
    public static Session getSession() throws HibernateException {
        Session session = (Session) threadLocal.get();

      if (session == null || !session.isOpen()) {
         if (sessionFactory == null) {
            rebuildSessionFactory();
         }
         session = (sessionFactory != null) ? sessionFactory.openSession()
               : null;
         threadLocal.set(session);
      }

        return session;
    }

   /**
     *  Rebuild hibernate session factory
     *
     */
   /*public synchronized static void rebuildSessionFactory() {
      try {
         configuration.configure(configFile);
         sessionFactory = configuration.buildSessionFactory();
      } catch (Exception e) {
         System.err
               .println("%%%% Error Creating SessionFactory %%%%");
         e.printStackTrace();
      }
   }*/
    
    public synchronized static void rebuildSessionFactory() {
        if (sessionFactory != null)
            return;
        
        try {
            configuration.configure(configFile);
            sessionFactory = configuration.buildSessionFactory();
            } 
        catch (Exception e) {
            System.err
        .println("%%%% Error Creating SessionFactory %%%%");
            e.printStackTrace();
        }
    }

   /**
     *  Close the single hibernate session instance.
     *
     *  @throws HibernateException
     */
    public static void closeSession() throws HibernateException {
        Session session = (Session) threadLocal.get();
        threadLocal.set(null);

        if (session != null) {
            session.close();
        }
    }

   /**
     *  return session factory
     *
     */
   public static org.hibernate.SessionFactory getSessionFactory() {
      return sessionFactory;
   }

   /**
     *  return session factory
     *
     *   session factory will be rebuilded in the next call
     */
   public static void setConfigFile(String configFile) {
      HibernateSessionFactory.configFile = configFile;
      sessionFactory = null;
   }

   /**
     *  return hibernate configuration
     *
     */
   public static Configuration getConfiguration() {
      return configuration;
   }
   
}

Also ive gone through the similar problem on http://www.myeclipseide.com/PNphpBB2-printview-t-15149-start-0.html

any help will be highly appreciated

MyEclipse v 6.0
Hibernate v 3.1.3

[darkapple]

after few hours of search i came to the mistake i’ve made. It’s not the HibernateSessionFactory causing the error, its the hbm.cfg configuration file for a table causing trouble.

I forgot to give full class name with package in one-to-many tag of set Here is the corrected one.

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- 
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
    <class name="com.library.Customer" table="customer" catalog="library">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="increment" />
        </id>
         <set name="books" inverse="false">
            <key><column name="customer_fk"></column></key>
            <one-to-many class="com.library.Book"/>
                       ^----------------------------^-
        </set>
        
        <property name="firstname" type="java.lang.String">
            <column name="firstname" />
        </property>
        <property name="lastname" type="java.lang.String">
            <column name="lastname" />
        </property>
        <property name="age" type="java.lang.Integer">
            <column name="age" />
        </property>
    </class>
</hibernate-mapping>

[Loyal Water]

Glad you got this sorted out.

[Author]

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