private static String read(Path path) {
        try {
            return new String(Files.readAllBytes(path), StandardCharsets.UTF_8);
        } catch (IOException e) {
            log.error("Could not read file {} for property {}", path, path.getFileName(), e);
            throw new ConfigException("Could not read file " + path + " for property " + path.getFileName());
        }
    }
Retrieves the data contained in the regular files named by {@code keys} in the directory given by {@code path}.
Non-regular files (such as directories) in the given directory are silently ignored.
@param path the directory where data files reside.
@param keys the keys whose values will be retrieved.
@return the configuration data.
clients/src/main/java/org/apache/kafka/common/config/provider/DirectoryConfigProvider.java