Resolve DBRef into Json

You have to import the DBRef Codec for it to print it, if u want it in a document json style you need to write your own Codec for DBRef and add it to the codecregistry you give toJson().

e.g.

CodecRegistry codecRegistry = CodecRegistries.fromRegistries(MongoClient.getDefaultCodecRegistry());
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final DocumentCodec codec = new DocumentCodec(codecRegistry, new BsonTypeClassMap());
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System.out.println(document.toJson(codec));