Implementation defined in superinterface's default method does not know about the internals of map, thus operate with less efficiency, e.g. merge() must do 2 hash lookup instead of one. Implementing these in subclass allow better performance should client code take use of these optional features.
Implementation defined in superinterface's default method does not know about the internals of map, thus operate with less efficiency, e.g. merge() must do 2 hash lookup instead of one. Implementing these in subclass allow better performance should client code take use of these optional features.