List<ExtraDirectoryParameters> getExtraDirectories() {
    // TODO: Should inform user about nonexistent directory if using custom directory.
    String property = getProperty(PropertyNames.EXTRA_DIRECTORIES_PATHS);
    if (property != null) {
      List<String> paths = ConfigurationPropertyValidator.parseListProperty(property);
      return paths.stream()
          .map(path -> new ExtraDirectoryParameters(new File(path), "/"))
          .collect(Collectors.toList());
    }
    return extraDirectories.getPaths();
  }
Gets the list of configured extra directory paths.

@return the list of configured extra directory paths
jib-maven-plugin/src/main/java/com/google/cloud/tools/jib/maven/JibPluginConfiguration.java