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Xerces2 is the next generation of high performance, fully compliant XML parsers in the Apache Xerces family. This new version of Xerces introduces the Xerces Native Interface (XNI), a complete framework for building parser components and configurations that is extremely modular and easy to program. The Apache Xerces2 parser is the reference implementation of XNI but other parser components, configurations, and parsers can be written using the Xerces Native Interface. For complete design and implementation documents, refer to the XNI Manual. Xerces2 is a fully conforming XML Schema 1.0 processor. A partial experimental implementation of the XML Schema 1.1 Structures and Datatypes Working Drafts (December 2009) and an experimental implementation of the XML Schema Definition Language (XSD): Component Designators (SCD) Candidate Recommendation (January 2010) are provided for evaluation. For more information, refer to the XML Schema page. Xerces2 also provides a complete implementation of the Document Object Model Level 3 Core and Load/Save W3C Recommendations and provides a complete implementation of the XML Inclusions (XInclude) W3C Recommendation. It also provides support for OASIS XML Catalogs v1.1. Xerces2 is able to parse documents written according to the XML 1.1 Recommendation, except that it does not yet provide an option to enable normalization checking as described in section 2.13 of this specification. It also handles namespaces according to the XML Namespaces 1.1 Recommendation, and will correctly serialize XML 1.1 documents if the DOM level 3 load/save APIs are in use.

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This package provides an API for validation of XML documents. Validation is the process of verifying that an XML document is an instance of a specified XML schema. An XML schema defines the content model (also called a grammar or vocabulary) that its instance documents will represent. There are a number of popular technologies available for creating an XML schema. Some of the most popular include: Document Type Definition (DTD) - XML's built-in schema language. W3C XML Schema (WXS) - an object-oriented XML schema language. WXS also provides a type system for constraining the character data of an XML document. WXS is maintained by the World Wide Web Consortium (W3C) and is a W3C Recommendation (that is, a ratified W3C standard specification). RELAX NG (RNG) - a pattern-based, user-friendly XML schema language. RNG schemas may also use types to constrain XML character data. RNG is maintained by the Organization for the Advancement of Structured Information Standards (OASIS) and is both an OASIS and an ISO (International Organization for Standardization) standard. Schematron - a rules-based XML schema language. Whereas DTD, WXS, and RNG are designed to express the structure of a content model, Schematron is designed to enforce individual rules that are difficult or impossible to express with other schema languages. Schematron is intended to supplement a schema written in structural schema language such as the aforementioned. Schematron is in the process of becoming an ISO standard. Previous versions of JAXP supported validation as a feature of an XML parser, represented by either a {@link javax.xml.parsers.SAXParser} or {@link javax.xml.parsers.DocumentBuilder} instance. The JAXP validation API decouples the validation of an instance document from the parsing of an XML document. This is advantageous for several reasons, some of which are: Support for additional schema languages. As of JDK 1.5, the two most popular JAXP parser implementations, Crimson and Xerces, only support a subset of the available XML schema languages. The Validation API provides a standard mechanism through which applications may take of advantage of specialization validation libraries which support additional schema languages. Easy runtime coupling of an XML instance and schema. Specifying the location of a schema to use for validation with JAXP parsers can be confusing. The Validation API makes this process simple (see example below). Usage example. The following example demonstrates validating an XML document with the Validation API (for readability, some exception handling is not shown): // parse an XML document into a DOM tree DocumentBuilderFactory parserFactory = DocumentBuilderFactory.newInstance(); parserFactory.setNamespaceAware(true); DocumentBuilder parser = parserFactory.newDocumentBuilder(); Document document = parser.parse(new File("instance.xml")); // create a SchemaFactory capable of understanding WXS schemas SchemaFactory factory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI); // load a WXS schema, represented by a Schema instance Source schemaFile = new StreamSource(new File("mySchema.xsd")); Schema schema = factory.newSchema(schemaFile); // create a Validator instance, which can be used to validate an instance document Validator validator = schema.newValidator(); // validate the DOM tree try { validator.validate(new DOMSource(document)); } catch (SAXException e) { // instance document is invalid! } The JAXP parsing API has been integrated with the Validation API. Applications may create a {@link javax.xml.validation.Schema} with the validation API and associate it with a {@link javax.xml.parsers.DocumentBuilderFactory} or a {@link javax.xml.parsers.SAXParserFactory} instance by using the {@link javax.xml.parsers.DocumentBuilderFactory#setSchema(Schema)} and {@link javax.xml.parsers.SAXParserFactory#setSchema(Schema)} methods. You should not both set a schema and call setValidating(true) on a parser factory. The former technique will cause parsers to use the new validation API; the latter will cause parsers to use their own internal validation facilities. Turning on both of these options simultaneously will cause either redundant behavior or error conditions.