Empty maps are deserialized as null

[gugumonster]

When configuring the mapper to also store empties

mapper.getOptions().setStoreEmpties(true);

then empty Maps and Lists are stored as well to DB.
They also get deserialized as empty Maps resp. List again.
This works for an empty

Map<String, String>

BUT it does not work for empty Maps like the following

Map<String, List<String>>
Map<String, MyObject>

where

class MyObject {
   private String valueA;
   private int valueB;
}

It seems when having a complex type in the value part of the map, the map is no longer deserialized as empty map but simply as null object, which subsequently breaks the code as they are no longer equal after loading.

Tested with Morphia 1.0.1

[shils]

The issue seems to be that EmbeddedMapper#readMap doesn't take its MapperOptions' isStoreEmpties flag into account when deciding whether to set the map field's value. This doesn't occur for simple valued maps because a different Mapper implementation is used.

I've created a pull request with the necessary changes here #869.