@Override
    public String getId() {
        return StringUtils.defaultIfBlank(super.getId(), CasSimpleMultifactorAuthenticationProperties.DEFAULT_IDENTIFIER);
    }
This is {@link CasSimpleMultifactorAuthenticationProvider}.

@author Misagh Moayyed
@since 6.0.0
support/cas-server-support-simple-mfa-core/src/main/java/org/apereo/cas/mfa/simple/CasSimpleMultifactorAuthenticationProvider.java