Extend Core Services via custom plugin

Is it possible to extend core services functionality via custom plugins?
E.g. Shopware\Core\Checkout\Cart\Address\AddressValidator - I have to extend this class with my own validate method. I’m sure it is possible, but how I can to do it?
Sure, I know, how to extend classes, but I don’t know, how I can register my class for make it working instead of core class.
Thanks a lot!

The question is closed.
I did it through services.xml specifying the Shopware service as the service-id and my class as the service-class. It works)