apache/iceberg · error · IllegalArgumentException

Cannot initialize AdlsTokenCredentialProvider, missing no-ar

Error message

Cannot initialize AdlsTokenCredentialProvider, missing no-arg constructor: %s

What it means

AdlsTokenCredentialProviders.loadCredentialProvider reflectively instantiates a custom AdlsTokenCredentialProvider implementation from a class name. Instantiation requires a publicly accessible no-argument constructor; when DynConstructors cannot find one, this IllegalArgumentException is thrown wrapping the NoSuchMethodException.

Source

Thrown at azure/src/main/java/org/apache/iceberg/azure/AdlsTokenCredentialProviders.java:64

  }

  private static AdlsTokenCredentialProvider loadCredentialProvider(
      String impl, Map<String, String> properties) {
    if (Strings.isNullOrEmpty(impl)) {
      AdlsTokenCredentialProvider provider = defaultFactory();
      provider.initialize(properties);
      return provider;
    }

    DynConstructors.Ctor<AdlsTokenCredentialProvider> ctor;
    try {
      ctor =
          DynConstructors.builder(AdlsTokenCredentialProvider.class)
              .loader(AdlsTokenCredentialProviders.class.getClassLoader())
              .hiddenImpl(impl)
              .buildChecked();
    } catch (NoSuchMethodException e) {
      throw new IllegalArgumentException(
          String.format(
              "Cannot initialize AdlsTokenCredentialProvider, missing no-arg constructor: %s",
              impl),
          e);
    }

    AdlsTokenCredentialProvider provider;
    try {
      provider = ctor.newInstance();
    } catch (ClassCastException e) {
      throw new IllegalArgumentException(
          String.format(
              "Cannot initialize AdlsTokenCredentialProvider, %s does not implement AdlsTokenCredentialProvider.",
              impl),
          e);
    }

    provider.initialize(properties);

View on GitHub (pinned to 86d9c8fc54)

Solutions

Add a public no-argument constructor to the implementation class.
If the class needs configuration, implement the no-arg constructor and read config through the AdlsTokenCredentialProvider initialize/initialize-pair lifecycle methods instead of constructor parameters.
Verify the configured class name is the intended implementation and not a typo pointing at another class.

Example fix

// before
public MyTokenProvider(String account) { this.account = account; }
// after
public MyTokenProvider() { }
@Override public void initialize(Map<String, String> properties) { this.account = properties.get("account"); }

Defensive patterns

Strategy: validation

Validate before calling

Class<?> cls = Class.forName(implClassName);
if (!AdlsTokenCredentialProvider.class.isAssignableFrom(cls)) throw new IllegalArgumentException(implClassName + " is not an AdlsTokenCredentialProvider");
try { cls.getDeclaredConstructor(); } catch (NoSuchMethodException e) { throw new IllegalArgumentException(implClassName + " needs a public no-arg constructor"); }

Try / catch

try { provider = AdlsTokenCredentialProviders.from(config); } catch (IllegalArgumentException e) { log.error("Bad credential provider config: {}", e.getMessage()); throw e; }

Prevention

Always give custom providers a public no-arg constructor.
Move configuration into the provider's initialize lifecycle method instead of constructors.
Unit-test reflective loading of your custom provider class.

When it happens

Trigger: Passing a class name via the ADLS token credential provider config (e.g. the azure credential provider impl property) that points to a class with no public no-arg constructor.

Common situations: Custom credential provider classes that only define parameterized constructors; classes requiring DI or config in constructor; anonymous/inner classes without a no-arg constructor.

Related errors

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/4227524f77d3fa8e. Report an issue: GitHub.