private static JsonArray getArray(JsonObject root, String key) {
        JsonElement element = root.get(key);
        if (element == null) {
            return new JsonArray();
        }
        Preconditions.checkArgument(element instanceof JsonArray);
        return (JsonArray) element;
    }
Deserializes a {@link SubjectDataContainer} container from a json object

@param service the permission service
@param root the root json object
@return a container representing the json data
sponge/src/main/java/me/lucko/luckperms/sponge/service/model/persisted/SubjectDataContainer.java