Declaration of beans and Dao classes in Spring

Declaration of beans and Dao classes in Spring

Spring give the facility of defining beans class and DAO classes in
application-context.xml file right now i am defining the bean classes like
that
<context:component-scan base-package="com.forum.jsfbeans" />
But many places in google i saw people defined DAO,beans,Service classes
differently something like this
<!-- Beans Declaration -->
<bean id="User" class="com.otv.model.User"/>
<!-- User Service Declaration -->
<bean id="UserService" class="com.otv.user.service.UserService">
<property name="userDAO" ref="UserDAO" />
</bean>
<!-- User DAO Declaration -->
<bean id="UserDAO" class="com.otv.user.dao.UserDAO">
<property name="sessionFactory" ref="SessionFactory" />
</bean>
we have to defined all the classes in application-context.xml file
differently(like i did above) or we can just use the below tag for each
type of classes not a matter its DAO,Bean or Service?
<context:component-scan
base-package="com.forum.dao,com.forum.jsfbeans,com.forum.service" />
If we will defined something like above it will work and Spring know what
action it have to perform in DAO,Service or Bean classes .