ConversionServiceFactoryBean error in spring-config.xml file

I am using this bean in an application of mine.

The application runs fine but the compiler produces a warning when I am trying to use the list tag :

<bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean">        <property name="converters">            <list>                <bean class="foo.bar.converter.StringToDateTimeConverter"/>            </list>        </property>    </bean>