Map and Collection sub-classes seem to lose generic information for deserialization

It looks like deserializing of following class:

static class MapSubClass extends HashMap<String,MyClass> { }

does not work as expected; instead of properly bound and typed content, deserialization works as if type was specified as Map<Object,Object>.
Same occurs with Collection types as well.

In addition, looks like @JsonDeserialize annotation is not properly (or at least completely) handled with Map/Collection types either.