No bean named 'entityManagerFactory' is defined

framework unabel to locate entityManagerFactory.

this is my app.xml
-------------------------
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalEntityMana gerFactoryBean">
<property name="persistenceUnitName" value="exams" />
</bean>

persistance.xml
---------
<persistence-unit name="exams" transaction-type="RESOURCE_LOCAL" >
-----
---
</persistence-unit>

----------------------------------
and persistance.xml is in web/inf/lib/xyz-dao.jar