Class userClass = userData.getClass();
while (userClass != null) {
for (final Field field : userClass.getDeclaredFields()) {
Arg ann = field.getAnnotation(Arg.class);
if (ann != null) {
String argDest = ann.dest();
if (argDest.isEmpty()) {
argDest = field.getName();
}
if (!attrs.containsKey(argDest)) {
continue;