private static String response(ResponseType type, Object... attributes) { final StringBuilder builder = new StringBuilder("{"); builder.append("\"status\":\"").append(type).append("\""); if (attributes.length > 0) { for (int i = 0; i < attributes.length; ) { final String key = attributes[i++].toString(); final Object value = attributes[i++]; if (value != null) { builder.append(String.format(",\"%s\":%s", key, JsonUtil.toJson(value))); } } } return builder.append("}").toString(); }