pentaho/pentaho-kettle · error · KettleException

Constructor not found for

Error message

Constructor not found for 

What it means

Companion to 'Can't create object': after scanning the constructors of the target class, createObject() found no no-arg constructor and no single-arg constructor accepting the root, and throws this KettleException.

Solutions

1. Add a public no-arg constructor
2. Add a public constructor whose single parameter type is assignable from the root class
3. Change the injection property type to a class with a supported constructor

Example fix

// before
class Child { public Child(String mandatory){...} }
// after
class Child { public Child(){...} public Child(String mandatory){...} }

// Same constructor-shape check as the create-failure variant
boolean hasCtor = Arrays.stream(targetClass.getConstructors()).anyMatch(k ->
  k.getParameterCount() == 0
  || (k.getParameterCount() == 1 && k.getParameterTypes()[0].isAssignableFrom(rootClass)));
if (!hasCtor) throw new IllegalStateException("Constructor not found for " + targetClass);

static boolean hasSupportedConstructor(Class<?> c, Class<?> root) {
  try { c.getDeclaredConstructor(); return true; }
  catch (NoSuchMethodException e) {
    return Arrays.stream(c.getConstructors()).anyMatch(k ->
      k.getParameterCount() == 1 && k.getParameterTypes()[0].isAssignableFrom(root));
  }
}

try {
  injector.injectValue(bean, path, value);
} catch (KettleException e) {
  if (e.getMessage().startsWith("Constructor not found")) {
    log.error("Add a no-arg or root-arg constructor for: " + e.getMessage(), e);
  } else throw e;
}

When it happens

Trigger: Reflection-based instantiation of a nested injection-path class where only constructors with incompatible signatures exist (e.g. required extra parameters).

Common situations: Value objects with builder-only construction; classes requiring DI-injected dependencies; Kotlin/Java classes with mandatory constructor args.

Related errors

• Can't create object
• DefaultAuthenticationConsumerFactory.Constructor
• DefaultAuthenticationConsumerFactory.Constructor.Arg
• No field or getter defined for
• No field or setter defined for

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/4e58c3b750f8b044. Report an issue: GitHub.

Appendix: source

Thrown at engine/src/main/java/org/pentaho/di/core/injection/bean/BeanInjector.java:342

      }
    }
    return true;
  }

  private Object createObject( Class<?> clazz, Object root ) throws KettleException {
    try {
      // Object can be inner of metadata class. In this case constructor will require parameter
      for ( Constructor<?> c : clazz.getConstructors() ) {
        if ( c.getParameterTypes().length == 0 ) {
          return clazz.newInstance();
        } else if ( c.getParameterTypes().length == 1 && c.getParameterTypes()[0].isAssignableFrom( info.clazz ) ) {
          return c.newInstance( root );
        }
      }
    } catch ( Throwable ex ) {
      throw new KettleException( "Can't create object " + clazz, ex );
    }
    throw new KettleException( "Constructor not found for " + clazz );
  }

  private Object extendArray( BeanLevelInfo s, Object obj, int newSize ) throws Exception {
    Object existArray = s.field.get( obj );
    if ( existArray == null ) {
      existArray = Array.newInstance( s.leafClass, newSize );
      s.field.set( obj, existArray );
    }
    int existSize = Array.getLength( existArray );
    if ( existSize < newSize ) {
      Object newSized = Array.newInstance( s.leafClass, newSize );
      System.arraycopy( existArray, 0, newSized, 0, existSize );
      existArray = newSized;
      s.field.set( obj, existArray );
    }

    return existArray;
  }

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