About the doc 1.4... what do they mean with a "custom repository functionality" ?

I'm reading again the documentation at <a href="http://forum.springsource.org/showthread.php?136894-Avoiding-data-related-code-spilling-out-into-the-service-layer&p=444362#post444362">Custom implementations</a> and I wonder what is it that is considered custom that is supposed to be implemented in here.

Is it all methods that cannot be done using the methods names nor the @Query annoation in the interfaces ?

I still wonder what to implement using a method name or using the @Query annotation, and what to implement using a method body, and for that latter case, how to implement it.

Any tips or directions would be very welcome...

Thanks !