apache/hadoop · error · IOException

{className} not found.

Error message

{className} not found.

What it means

Error "{className} not found." thrown in apache/hadoop.

Source

Thrown at hadoop-tools/hadoop-aliyun/src/main/java/org/apache/hadoop/fs/aliyun/oss/AliyunOSSUtils.java:130

      Configuration newConf =
          ProviderUtils.excludeIncompatibleCredentialProviders(conf,
              AliyunOSSFileSystem.class);
      credentials = new AliyunCredentialsProvider(newConf);
    } else {
      try {
        LOG.debug("Credential provider class is:" + className);
        Class<?> credClass = Class.forName(className);
        try {
          credentials =
              (CredentialsProvider)credClass.getDeclaredConstructor(
                  URI.class, Configuration.class).newInstance(uri, conf);
        } catch (NoSuchMethodException | SecurityException e) {
          credentials =
              (CredentialsProvider)credClass.getDeclaredConstructor()
              .newInstance();
        }
      } catch (ClassNotFoundException e) {
        throw new IOException(className + " not found.", e);
      } catch (NoSuchMethodException | SecurityException e) {
        throw new IOException(String.format("%s constructor exception.  A " +
            "class specified in %s must provide an accessible constructor " +
            "accepting URI and Configuration, or an accessible default " +
            "constructor.", className, CREDENTIALS_PROVIDER_KEY),
            e);
      } catch (ReflectiveOperationException | IllegalArgumentException e) {
        throw new IOException(className + " instantiation exception.", e);
      }
    }

    return credentials;
  }

  /**
   * Turns a path (relative or otherwise) into an OSS key, adding a trailing
   * "/" if the path is not the root <i>and</i> does not already have a "/"
   * at the end.

View on GitHub (pinned to 2add963021)

Solutions

1. Ensure the named class is on the classpath; check the configuration key naming the class for typos.

When it happens

Trigger: Thrown at hadoop-tools/hadoop-aliyun/src/main/java/org/apache/hadoop/fs/aliyun/oss/AliyunOSSUtils.java:130 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/51a757f6fad4bc5f. Report an issue: GitHub.