Can gson deserialize empty strings as nulls inside a map?

I've got a remote API responding with json structured like this:

{ 
  "something": 1234,
  "message": "abcde",
  "someKey": null,
  "Results": [
    {
     "key1": "",
     "key2": "some value here",
     "key3": ""
    }
  ]
}

The problem is that there are hundreds of these empty string values being returned making it hard to sort through the results. I've tried registering and implementing my own JsonDeserializer like this:

    public static class EmptyStringAsNullTypeAdapter<T> implements JsonSerializer<T>, JsonDeserializer<T> {
        @Override
        public JsonElement serialize(T src, Type typeOfSrc, JsonSerializationContext context) {
            if(StringUtils.isBlank(src.toString())) return null;
            return new JsonPrimitive(src.toString());
        }

        @Override
        public T deserialize(final JsonElement jsonElement, Type type, final JsonDeserializationContext context) throws JsonParseException {
            if ( jsonElement.isJsonPrimitive() ) {
                final JsonPrimitive jsonPrimitive = jsonElement.getAsJsonPrimitive();
                if ( jsonPrimitive.isString() && jsonPrimitive.getAsString().isEmpty() ) {
                    return null;
                }
            }
            return context.deserialize(jsonElement, type);
        }
    }

        GsonBuilder gsonBuilder = new GsonBuilder();
        gsonBuilder.registerTypeAdapter(JsonElement.class, new EmptyStringAsNullTypeAdapter());
    // gsonBuilder.registerTypeAdapter(String.class, new EmptyStringAsNullTypeAdapter());  //tried this first
        Gson gson = gsonBuilder.create();

        JsonParser jp = new JsonParser();
        JsonElement je = jp.parse(jsonString);

        String prettyJson = gson.toJson(je);

Doesn't seem to matter what I do here, the custom Deserializer never gets called and my "prettyJson" always contains the empty strings I'm trying to avoid. I've also tried adding a custom serializer but it also never gets called. Can gson do what I'd like it to do here and if so, how?

Here is what I want:

{ 
  "something": 1234,
  "message": "abcde",
  "Results": [
    {
     "key2": "some value here",
    }
  ]
}

You need to implement JsonSerializer here you are again serializing the object in string.