pentaho/pentaho-kettle · error · org.pentaho.di.core.exception.KettleValueException

KettleValueException wrapping KettlePluginException from…

Error message

KettleValueException wrapping KettlePluginException from cloneToType (no message; cause carries detail)

What it means

cloneToType creates a new RowMeta of a target type (e.g. to clone metadata between binary/string representations). The RowMeta copy constructor may throw KettlePluginException when ValueMetaFactory cannot create a value meta of the requested type. RowMeta translates that into a KettleValueException because cloneToType's signature only declares KettleValueException; the root cause and its message are carried on the exception's cause.

Solutions

Inspect getCause() of the KettleValueException to find the underlying KettlePluginException detail message.
Verify all Kettle value-type plugin jars are present on the classpath / in the plugins directory.
Ensure the PDI core and plugin versions match the target value type; upgrade/downgrade to a consistent set of jars.
If wrapping a custom ValueMeta, confirm its class is public, has a no-arg/copy constructor, and is registered with ValueMetaFactory.

Example fix

// before
RowMetaInterface stringClone = rowMeta.cloneToType(ValueMetaInterface.TYPE_STRING);
// after
try {
  RowMetaInterface stringClone = rowMeta.cloneToType(ValueMetaInterface.TYPE_STRING);
} catch (KettleValueException e) {
  log.error("cloneToType failed: " + (e.getCause() != null ? e.getCause().getMessage() : e.getMessage()), e);
  throw e;
}

Defensive patterns

Strategy: try-catch

Validate before calling

if (rowMeta == null || rowMeta.size() == 0) { throw new IllegalStateException("Cannot clone empty RowMeta"); }

Try / catch

try {
  RowMetaInterface clone = rowMeta.cloneToType(ValueMetaInterface.TYPE_STRING);
} catch (KettleValueException e) {
  Throwable cause = e.getCause();
  log.error("cloneToType failed: " + (cause != null ? cause.getMessage() : e.getMessage()), e);
}

Prevention

Ship all value-type plugin jars with your PDI installation.
Keep PDI core and plugin versions consistent.
Log e.getCause() rather than only the wrapper's (empty) message.

When it happens

Trigger: Calling rowMeta.cloneToType(ValueMetaInterface.TYPE_...) where cloning a value meta requires the plugin factory to instantiate a value class that is missing, not registered, or whose constructor fails (e.g. an unknown/removed value type plugin on the classpath).

Common situations: PDI plugin jar missing from plugins/ directory so a custom value type cannot be instantiated; version mismatch where a value type class was renamed/moved between Pentaho/PDI versions; classloader issues when embedding Kettle in an application.

Understand the failure class

Background: "not installed", "pip install", "required for": how missing-dependency errors surface across open-source libraries — this error's family across 34 libraries.

Related errors

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/7f36306054ff3886. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/pentaho/di/core/row/RowMeta.java:108

    } finally {
      lock.readLock().unlock();
    }
  }

  /**
   * This method copies the row metadata and sets all values to the specified type (usually String)
   *
   * @param targetType The target type
   * @return The cloned metadata
   * @throws if the target type could not be loaded from the plugin registry
   */
  @Override
  public RowMetaInterface cloneToType( int targetType ) throws KettleValueException {
    lock.readLock().lock();
    try {
      return new RowMeta( this, targetType );
    } catch ( KettlePluginException e ) {
      throw new KettleValueException( e );
    } finally {
      lock.readLock().unlock();
    }
  }

  @Override
  public String toString() {
    StringBuilder buffer = new StringBuilder();
    lock.readLock().lock();
    try {
      boolean notFirst = false;
      for ( ValueMetaInterface valueMeta : valueMetaList ) {
        if ( notFirst ) {
          buffer.append( ", " );
        } else {
          notFirst = true;
        }
        buffer.append( "[" ).append( valueMeta.toString() ).append( "]" );

View on GitHub (pinned to f3058517a1)