Rule Definition
Auto-wiring can save you time in small applications, but in many cases, it leads to bad practices and is inflexible in large applications. Using byName seems like a good idea, but it may lead you to give your classes artificial property names so that you can take advantage of the auto-wiring functionality. The whole idea behind Spring is that you can create your classes how you like and have Spring work for you, not the other way around. You may be tempted to use byType until you realize that you can only have one bean for each type in your BeanFactory -- a restriction that is problematic when you need to maintain beans with different configurations of the same type. Also it will affect the performance of your application since auto-wiring is slow.

Remediation
Define your wiring explicitly, and you benefit from explicit semantics and full flexibility on property naming and on how many instances of the same type you manage.

Violation Code Sample

<beans>
   <bean id="myBean" autowire="byName" class="com.cast.MyBean"/> // VIOLATION
...
</beans>

Fixed Code Sample

<beans>
   <bean id="myBean" class="com.cast.MyBean"/> // FIXED
...
</beans>

http://www.onjava.com/pub/a/onjava/2006/01/25/spring-xml-configuration-best-practices.html http://code.google.com/p/google-guice/wiki/SpringComparison