How to auto detect entities in JPA 2.0

Since Spring 3.1, you also have the option to forget persistence.xml altogether, and configure your EntityManagerFactory using the packagesToScan property, similar to this:

<bean id="entityManagerFactory" 
      class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
      p:dataSource-ref="dataSource"
      p:packagesToScan="${jpa.entity.packages}">

    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"
              p:showSql="${hibernate.show_sql}"/>
    </property>

    <property name="jpaProperties">
        <props>
            <prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
            <prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>
        </props>
    </property>
</bean>

See Pascal Thivent answer here : Do I need <class> elements in persistence.xml?

you have different way to do it, but JPA itself does not support auto-scan. The simplest and cleanest way to reference your entities IMHO is to package your model in a jar and to reference it with <jar-file>MyModel.jar</jar-file>