apache/hadoop · error · IllegalArgumentException

Configuration {className} not defined/accessible.

Error message

Configuration  {className} not defined/accessible.

What it means

Error "Configuration {className} not defined/accessible." thrown in apache/hadoop.

Source

Thrown at hadoop-tools/hadoop-azure-datalake/src/main/java/org/apache/hadoop/fs/adl/AdlFileSystem.java:255

   * configuration object is loaded to retrieve token configuration as specified
   * is documentation.
   *
   * Custom token management takes the higher precedence during initialization.
   *
   * @param conf Configuration object
   * @return null if the no custom {@link AzureADTokenProvider} token management
   * is specified.
   * @throws IOException if failed to initialize token provider.
   */
  protected synchronized AzureADTokenProvider getCustomAccessTokenProvider(
      Configuration conf) throws IOException {
    String className = getNonEmptyVal(conf, AZURE_AD_TOKEN_PROVIDER_CLASS_KEY);

    Class<? extends AzureADTokenProvider> azureADTokenProviderClass =
        conf.getClass(AZURE_AD_TOKEN_PROVIDER_CLASS_KEY, null,
            AzureADTokenProvider.class);
    if (azureADTokenProviderClass == null) {
      throw new IllegalArgumentException(
          "Configuration  " + className + " " + "not defined/accessible.");
    }

    azureTokenProvider = ReflectionUtils
        .newInstance(azureADTokenProviderClass, conf);
    if (azureTokenProvider == null) {
      throw new IllegalArgumentException("Failed to initialize " + className);
    }

    azureTokenProvider.initialize(conf);
    return azureTokenProvider;
  }

  private AccessTokenProvider getAccessTokenProvider(Configuration config)
      throws IOException {
    Configuration conf = ProviderUtils.excludeIncompatibleCredentialProviders(
        config, AdlFileSystem.class);
    TokenProviderType type = conf.getEnum(

View on GitHub (pinned to 2add963021)

Solutions

1. Ensure the named class is on the classpath and accessible (public constructor).
2. Check the configuration key naming the class for typos.

When it happens

Trigger: ADL filesystem fails to load a configured class during initialization.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/8c97d2e5cbcf4031. Report an issue: GitHub.