java.lang.NullPointerException

一直都是报上面的错，网上查了很久，一直都是说没实例化，可我明明都配好了呀。求大神指导，下面是部分配置(SSH)：

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.format_sql">true</prop>
<prop key="hibernate.hbm2ddl.auto">update</prop>
</props>
</property>