@Override
    public void configure(Map<String, ?> configs, String contextName, Configuration configuration,
                          AuthenticateCallbackHandler loginCallbackHandler) {
        this.contextName = contextName;
        this.configuration = configuration;
        this.loginCallbackHandler = loginCallbackHandler;
    }
Base login class that implements methods common to typical SASL mechanisms.
clients/src/main/java/org/apache/kafka/common/security/authenticator/AbstractLogin.java