error

Hibernate config
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration SYSTEM
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
   <session-factory>
   <property name="hibernate.dialect">
      org.hibernate.dialect.H2Dialect
   </property>
   <property name="hibernate.connection.driver_class">
     org.h2.Driver
   </property>

   <!-- Assume test is the database name -->
   <property name="hibernate.connection.url">
      jdbc:h2:tcp://localhost/~/Nueva
   </property>
   <property name="hibernate.connection.username">
      sa
   </property>
   <property name="hibernate.connection.password"></property>

   <!-- List of XML mapping files -->

   <mapping resource="negocio/Curso.hbm.xml"/>
	<mapping resource="negocio/Profesor.hbm.xml"/>
	 <mapping resource="negocio/Empleado.hbm.xml"/>
</session-factory>
</hibernate-configuration>



Curso.hbm.xml
<hibernate-mapping>
   <class name="negocio.Curso" table="CURSO">
      <meta attribute="class-description">
         This class contains the employee detail.
      </meta>
      <id name="idCurso" type="int" column="id_curso">
         <generator class="native"/>
      </id>
      <property name="descripcion" column="descripcion" type="string"/>

      <many-to-one name="profesor" column="id_profesor"
       class="negocio.Profesor" not-null="true"/>
   </class>
</hibernate-mapping>