public static Item fromJSON(String json) {
        if (json == null)
            return null;
        @SuppressWarnings("unchecked")
        Map<String, Object> map = (Map<String, Object>)
            valueConformer.transform(Jackson.fromJsonString(json, Map.class));
        return fromMap(map);
    }
Convenient factory method - instantiates an <code>Item</code> from the
given JSON string.

@return an <code>Item</code> initialized from the given JSON document;
or null if the input is null.
aws-java-sdk-dynamodb/src/main/java/com/amazonaws/services/dynamodbv2/document/Item.java