@SuppressWarnings("unchecked")
    public ActionRequestFailureHandler<DocWriteRequest<?>> getFailureHandler() {
        final ActionRequestFailureHandler<DocWriteRequest<?>> failureHandler;
        String value = config.get(FAILURE_HANDLER_OPTION);
        switch (value.toUpperCase()) {
            case "FAIL":
                failureHandler = new NoOpFailureHandler<>();
                break;
            case "IGNORE":
                failureHandler = new IgnoringFailureHandler<>();
                break;
            case "RETRY-REJECTED":
                failureHandler = new RetryRejectedExecutionFailureHandler();
                break;
            default:
                try {
                    Class<?> failureHandlerClass = Class.forName(value, false, getClassLoader());
                    failureHandler = (ActionRequestFailureHandler<DocWriteRequest<?>>) InstantiationUtil
                            .instantiate(failureHandlerClass);
                } catch (ClassNotFoundException e) {
                    throw new ValidationException(
                            "Could not instantiate the failure handler class: " + value, e);
                }
                break;
        }
        return failureHandler;
    }
Parse Hosts String to list.

<p>Hosts String format was given as following:

<pre>
    connector.hosts = http://host_name:9092;http://host_name:9093
</pre>
inlong-sort/sort-flink/sort-flink-v1.13/sort-connectors/elasticsearch-6/src/main/java/org/apache/inlong/sort/elasticsearch6/table/Elasticsearch6Configuration.java