pentaho/pentaho-kettle · error · UIObjectCreationException

Unable to get the constructor for

Error message

Unable to get the constructor for 

What it means

UIObjectRegistry.constructUITransformation() looks up a Constructor<init>(RepositoryElementMetaInterface, UIRepositoryDirectory, Repository) on the registered transformation class via getConstructor(). If getConstructor() throws NoSuchMethodException, the code throws UIObjectCreationException 'Unable to get the constructor for ' + transClass. (The index's message text corresponds to the sibling instantiate branch, but this throw site fires when the required constructor signature is missing.)

Solutions

1. Add/fix a public constructor with the exact signature (RepositoryElementMetaInterface, UIRepositoryDirectory, Repository) in the registered class
2. Recompile the custom class against the current PDI UI library version
3. Remove the custom registration so the default UITransformation is used
4. Check that getConstructor's parameter types exactly match, including the Repository interface (not a concrete class)

Example fix

// before
public MyUITransformation( RepositoryElementMetaInterface rc, UIRepositoryDirectory parent ) { ... }
// after
public MyUITransformation( RepositoryElementMetaInterface rc, UIRepositoryDirectory parent, Repository rep ) { ... }

try {
  transClass.getConstructor(RepositoryElementMetaInterface.class, UIRepositoryDirectory.class, Repository.class);
} catch (NoSuchMethodException e) {
  throw new IllegalStateException(transClass + " lacks required UI constructor", e);
}

boolean hasUITransConstructor(Class<?> c) {
  try { c.getConstructor(RepositoryElementMetaInterface.class, UIRepositoryDirectory.class, Repository.class); return true; }
  catch (NoSuchMethodException e) { return false; }
}

try { UITransformation t = registry.constructUITransformation(rc, parent, rep); } catch (UIObjectCreationException e) { log.error("Constructor missing on " + e.getMessage(), e); UITransformation t = new UITransformation(rc, parent, rep); }

When it happens

Trigger: Registering a custom UITransformation subclass that does not declare a public constructor taking (RepositoryElementMetaInterface, UIRepositoryDirectory, Repository), so getConstructor() finds nothing.

Common situations: Custom registry extension after a PDI upgrade changed constructor signatures; class written against an older UITransformation API; typo'd or non-public constructor in a custom class.

Related errors

• Unable to get the constructor for
• Unable to instantiate object for
• Can't create object
• Constructor not found for
• DefaultAuthenticationConsumerFactory.Constructor

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/83907b158a171ac2. Report an issue: GitHub.

Appendix: source

Thrown at ui/src/main/java/org/pentaho/di/ui/repository/repositoryexplorer/model/UIObjectRegistry.java:128

        return (UIJob) constructor.newInstance( rc, parent, rep );
      } else {
        throw new UIObjectCreationException( "Unable to get the constructor for " + jobClass );
      }
    } catch ( Exception e ) {
      throw new UIObjectCreationException( "Unable to instantiate object for " + jobClass );
    }
  }

  public UITransformation constructUITransformation( RepositoryElementMetaInterface rc,
    UIRepositoryDirectory parent, Repository rep ) throws UIObjectCreationException {
    try {
      Constructor<?> constructor =
        transClass.getConstructor(
          RepositoryElementMetaInterface.class, UIRepositoryDirectory.class, Repository.class );
      if ( constructor != null ) {
        return (UITransformation) constructor.newInstance( rc, parent, rep );
      } else {
        throw new UIObjectCreationException( "Unable to get the constructor for " + transClass );
      }
    } catch ( Exception e ) {
      throw new UIObjectCreationException( "Unable to instantiate object for " + transClass );
    }
  }

  public UIRepositoryDirectory constructUIRepositoryDirectory( RepositoryDirectoryInterface rd,
    UIRepositoryDirectory uiParent, Repository rep ) throws UIObjectCreationException {
    try {
      Constructor<?> constructor =
        dirClass.getConstructor(
          RepositoryDirectoryInterface.class, UIRepositoryDirectory.class, Repository.class );
      if ( constructor != null ) {
        return (UIRepositoryDirectory) constructor.newInstance( rd, uiParent, rep );
      } else {
        throw new UIObjectCreationException( "Unable to get the constructor for " + dirClass );
      }
    } catch ( Exception e ) {

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