public static void postValidateSaslMechanismConfig(AbstractConfig config) {
        SecurityProtocol securityProtocol = SecurityProtocol.forName(config.getString(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG));
        String clientSaslMechanism = config.getString(SaslConfigs.SASL_MECHANISM);
        if (securityProtocol == SecurityProtocol.SASL_PLAINTEXT || securityProtocol == SecurityProtocol.SASL_SSL) {
            if (clientSaslMechanism == null || clientSaslMechanism.isEmpty()) {
                throw new ConfigException(SaslConfigs.SASL_MECHANISM, null, "When the " + CommonClientConfigs.SECURITY_PROTOCOL_CONFIG +
                        " configuration enables SASL, mechanism must be non-null and non-empty string.");
            }
        }
    }
Log warning if the exponential backoff is disabled due to initial backoff value is greater than max backoff value.

@param config                    The config object.
clients/src/main/java/org/apache/kafka/clients/CommonClientConfigs.java