pentaho/pentaho-kettle · error · RuntimeException

Wrong value conversion to

Error message

Wrong value conversion to 

What it means

getStringAsJavaType() converts a String value to a requested Java type via an InjectionTypeConverter during metadata injection. If destinationType is not one of the supported targets (String primitives, Boolean, enums, etc.), it throws a RuntimeException naming the type. It's a fail-fast guard for unsupported injection target types.

Solutions

1. Change the target property's Java type to a supported one (String, boolean/Boolean, int/Integer, enum)
2. Register/extend the InjectionTypeConverter to support the destination type
3. Convert the value manually before injection (e.g. pre-parse the string to the needed type)
4. Catch RuntimeException around the injection call and report the unsupported type

Example fix

// before
injection.setProperty("format", someDate, Date.class);
// after
injection.setProperty("format", someDate, String.class);

boolean isSupportedStringDestination(Class<?> t) {
  return String.class.isAssignableFrom(t) || t == boolean.class || Boolean.class.isAssignableFrom(t)
    || (t.isEnum());
}

boolean isSupportedStringDestination(Class<?> t) {
  return String.class.isAssignableFrom(t) || t == boolean.class
    || Boolean.class.isAssignableFrom(t) || t.isEnum();
}

try {
  Object v = row.getAsJavaType(name, destType, converter);
} catch (RuntimeException e) {
  if (e.getMessage().startsWith("Wrong value conversion")) {
    log.error("Unsupported destination type " + destType + " for field " + name, e);
  } else throw e;
}

When it happens

Trigger: Calling getAsJavaType (via setProperty) with a destinationType that falls through all isAssignableFrom checks in getStringAsJavaType — e.g. a non-String source field being injected into a destination type like Date, Map, List, or a primitive other than the supported ones.

Common situations: Metadata injection into a step whose setter expects a type (e.g. java.util.Date, BigDecimal, array) that the converter has no string conversion for; changing a field's Java type in a custom step without updating injection support.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Unknown conversion from
• Unknown source type:
• Unknown value for enum
• Wrong value conversion to
• : can't be converted to an Internet Address

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/dc1ed4b8fb8fb05e. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/pentaho/di/core/RowMetaAndData.java:337

    throws KettleValueException {
    if ( String.class.isAssignableFrom( destinationType ) ) {
      return converter.string2string( vs );
    } else if ( int.class.isAssignableFrom( destinationType ) ) {
      return converter.string2intPrimitive( vs );
    } else if ( Integer.class.isAssignableFrom( destinationType ) ) {
      return converter.string2integer( vs );
    } else if ( long.class.isAssignableFrom( destinationType ) ) {
      return converter.string2longPrimitive( vs );
    } else if ( Long.class.isAssignableFrom( destinationType ) ) {
      return converter.string2long( vs );
    } else if ( boolean.class.isAssignableFrom( destinationType ) ) {
      return converter.string2booleanPrimitive( vs );
    } else if ( Boolean.class.isAssignableFrom( destinationType ) ) {
      return converter.string2boolean( vs );
    } else if ( destinationType.isEnum() ) {
      return converter.string2enum( destinationType, vs );
    } else {
      throw new RuntimeException( "Wrong value conversion to " + destinationType );
    }
  }

  /**
   * Returns value as specified java type using converter. Used for metadata injection.
   */
  public Object getAsJavaType( String valueName, Class<?> destinationType, InjectionTypeConverter converter )
    throws KettleValueException {
    int idx = rowMeta.indexOfValue( valueName );
    if ( idx < 0 ) {
      throw new KettleValueException( "Unknown column '" + valueName + "'" );
    }

    ValueMetaInterface metaType = rowMeta.getValueMeta( idx );
    // find by source value type
    switch ( metaType.getType() ) {
      case ValueMetaInterface.TYPE_STRING:
        String vs = rowMeta.getString( data, idx );

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