|| userNameProp.getStringValue().trim().length() == 0) {
throw new IllegalArgumentException("User name not specified.");
}
String userName = userNameProp.getStringValue();
SubjectManagerLocal subjectManager = LookupUtil.getSubjectManager();
Subject subject = subjectManager.getSubjectByName(userName);
if (subject == null) {
throw new IllegalArgumentException("User '" + userName + "' doesn't exist.");
}