org.hibernate.MappingException: Unknown entity: annotations.Users

Question

Consider the hierarchy :

And the following classes and xml :

Answer 1

Define the Entity class in Hibernate.cfg.xml

<mapping class="com.supernt.Department"/>

While creating the sessionFactory object Load the Configuration file Like

SessionFactory factory = new AnnotationConfiguration().configure("hibernate.cfg.xml").buildSessionFactory();

Answer 2

 public static void main(String[] args) {
      try{
        // factory = new Configuration().configure().buildSessionFactory();
         factory = new AnnotationConfiguration().
                   configure().
                   //addPackage("com.xyz") //add package if used.
                   addAnnotatedClass(Employee.class).
                   buildSessionFactory();
      }catch (Throwable ex) { 
         System.err.println("Failed to create sessionFactory object." + ex);
         throw new ExceptionInInitializerError(ex); 
      }//you can write like this in your test class inside main method.this way you will be able to do the things using annotaions only

Answer 3

For those using Spring's Java configuration classes, you might write the following:

@Autowired
@Bean(name = "sessionFactory")
public SessionFactory getSessionFactory(DataSource dataSource) {
    LocalSessionFactoryBuilder sessionBuilder = new LocalSessionFactoryBuilder(dataSource);
    sessionBuilder.addProperties(getHibernateProperties());
    sessionBuilder.addAnnotatedClasses(Foo.class);
    sessionBuilder.addAnnotatedClasses(Bar.class);
    sessionBuilder.addAnnotatedClasses(Bat.class);
    return sessionBuilder.buildSessionFactory();
}

Answer 4

Add the following to your xml:

<bean id="sessionFactory"
    class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="packagesToScan">
        <list>
            <value>annotations</value>
        </list>
    </property>
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
            <prop key="hibernate.show_sql">true</prop>
        </props>
    </property>
</bean>

<tx:annotation-driven transaction-manager="transactionManager" />

<bean id="transactionManager"
    class="org.springframework.orm.hibernate4.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>

Answer 5

When I was trying to rewrite my example (from tutorialspoint) to use annotations, I got the same exception. This helped me (addAnnotatedClass()):

Configuration cfg=new Configuration(); 
cfg.addAnnotatedClass(com.tutorialspoint.hibernate.entity.Employee.class);
cfg.configure();

Answer 6

Use EntityScanner if you can bear external dependency.It will inject your all entity classes seamlessly even from multiple packages. Just add following line after configuration setup.

Configuration configuration = new Configuration().configure();    
EntityScanner.scanPackages("com.fz.epms.db.model.entity").addTo(configuration);
// And following depencency if you are using Maven
<dependency>
        <groupId>com.github.v-ladynev</groupId>
        <artifactId>fluent-hibernate-core</artifactId>
        <version>0.3.1</version>
</dependency>

This way you don't need to declare all entities in hibernate mapping file.