Hibernate Duplicate Import Exception

net.sf.hibernate.MappingException: duplicate import

I encountered this when I was using the ant net.sf.hibernate.tool.hbm2ddl.SchemaExportTask provided as part of the hibernate distribution. My original ant task is below.

<taskdef name="ddl"
         classname="net.sf.hibernate.tool.hbm2ddl.SchemaExportTask"
         classpathref="ddl.classpath"/>
<ddl config="src/com/magicmonster/intranet/service/hibernate.cfg.xml"
 quiet="no"
 text="no"
 drop="no"
 delimiter=";"
 output="export.sql">
  <fileset dir="src">
    <include name="**/*.hbm.xml"/>
  </fileset>
</ddl>

The duplicate exception is thrown because my configuration file, src/com/magicmonster/intranet/service/hibernate.cfg.xml, already tells hibernate to load up all the hbm.xml files. The examples in the docs assume that you’ve only got database configuration data inside the cfg.xml file. To amend this, I removed the fileset element from the task.