| Questions |

- Validation and infoset augmentation
- Default Parser Configuration
- Validation Features
- Validation against a specific schema language

| Answers |

| What's the result of having a DTD validator or XML Schema validator in the pipeline? |

| If a validator is included in the pipeline, the assessment is done, whether the validation feature is set to true or false. The validation feature only enables the validation constraint error reporting and it does not control the infoset augmentation: if a validator is included in the pipeline the parser will augment the infoset according to the grammar specified for the instance document.

| What validation behavior do I expect from the default parser configuration? |

The default configuration (org.apache.xerces.parsers.XML11Configuration) includes the DTD validator and the document scanner (which are both capable of namespace binding). Thus, the validation feature will enable validation against a DTD only. To allow validation against XML Schemas you must turn on the validation feature and the schema feature, and XML Schema Validator will be inserted in the pipeline. if you've created your own configuration which does not extend XML11Configuration (or another suitable configuration included with the parser), you must make sure that your configuration inserts all needed validators in the pipeline.

| What happens if I set both validation and schema validation features on? |

If both validators are present in the pipeline (this is the default behavior), then

- if the instance document has only a DTD grammar (DOCTYPE before the root element), then only DTD validation errors are reported;
- if the instance document has only XML Schema grammars, then only XML Schema validation errors are reported
- if the instance document has both DTD and XML Schema grammars, validation errors for both DTD and XML Schema are reported;
- if no grammar can be found for the instance document, the last validator in the pipeline will report validation errors.

An application may choose to create a configuration that does not have a DTD validator but has an XML Schema validator. This will turn Xerces into a non-compliant processor according to XML 1.0 and XML Schema specifications, thus the validation/augmentation outcome is undefined.

| How can I tell the parser to validate against XML Schema and not to report DTD validation errors? |

| Currently this is impossible. We hope that JAXP 1.2 will provide this capability via its schema language property. Otherwise, we might introduce a Xerces language property that will allow specifying the language against which validation will occur.