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New in Hibernate checked for similar problems in the forums but I couldn't find anything.

I am following the example on chapter 2 of documentation up to paragraph 2.2. When I try to run the application I am getting MappingException Error reading resource: Event.hbm.xml
What does this means exactly and how do I fix it;

I have created the database and user on MySQL and checked that the access rights are ok.


Hibernate version: 3.0.5

Mapping documents:The Event.hbm.xml is according to the documentation as well as the java files Event.Java, EventManager.java and HibernateUtil.java

<?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">
<hibernate-mapping>
<class name="Event" table="EVENTS">
<id name="id" column="EVENT_ID">
<generator class="increment"/>
</id>
<property name="date" type="timestamp" column="EVENT_DATE"/>
<property name="title"/>
</class>
</hibernate-mapping>


Code between sessionFactory.openSession() and session.close():

Full stack trace of any exception that occurs:

log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Initial SessionFactory creation failed.org.hibernate.MappingException: Error reading resource: Event.hbm.xml
Exception in thread "main" java.lang.ExceptionInInitializerError
at com.nn.Event.HibernateUtil.<clinit>(HibernateUtil.java:30)
at com.nn.Event.EventManager.createAndStoreEvent(EventManager.java:40)
at com.nn.Event.EventManager.main(EventManager.java:26)
Caused by: org.hibernate.MappingException: Error reading resource: Event.hbm.xml
at org.hibernate.cfg.Configuration.addResource(Configuration.java:452)
at org.hibernate.cfg.Configuration.parseMappingElement(Configuration.java:1263)
at org.hibernate.cfg.Configuration.parseSessionFactory(Configuration.java:1235)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1217)
at org.hibernate.cfg.Configuration.doConfigure(Configuration.java:1184)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1112)
at org.hibernate.cfg.Configuration.configure(Configuration.java:1098)
at com.nn.Event.HibernateUtil.<clinit>(HibernateUtil.java:26)
... 2 more
C
Name and version of the database you are using: MySQL 4.1.12-max

The generated SQL (show_sql=true):

Debug level Hibernate log excerpt:

I think it's having trouble finding the Event.hbm.xml file. Depending on how you've written your hibernate config file, you probably need to put Event.hbm.xml in the package with Event.java. If that doesn't do it for you, post your hibernate config file.

No that's not the problem. That's the message when not finding the file
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Initial SessionFactory creation failed.org.hibernate.MappingException: Resource: Event2.hbm.xml not found
Exception in thread "main" java.lang.ExceptionInInitializerError


The hibernate config file according to chapter 2 of the documentation
<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost/event</property>
<property name="connection.username">event</property>
<property name="connection.password">event</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>

<mapping resource="Event.hbm.xml"/>
</session-factory>
</hibernate-configuration>

If you have Event.hbm.xml in the package with Event, remove this line from your config.



Also (and I think this is the problem), you need to specify the package for Event somewhere in the mapping. So, if your event is in package.name, either:


or


If Event isn't in a package, I'm not sure what would be correct, except to say that you should put it in one ;)

Thanks that solved the problem. I tried both

and


and both solve the problem.

I have the Event.hbm.xml on the root of the src directory and it works fine.
I thought it will be better to have the mapping files together with the java classes but then I had to modify the hibernate.cfg.xml file to define the path of the mapping file in the package.


Is there any standard praxis regarding the location of the mapping files;

The preferred practice is to place an hbm.xml file for each persistent class in the package with the .java file. If you do this, then you need specify nothing in your hibernate.cfg.xml file to "import" the config. Instead, you simply add the class to your Configuration object before building the SessionFactory:



Hibernate will assume you have followed preferred practice.