Java Module java.xml Package javax.xml Class XMLConstants（JDK11）

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java.lang.Object
- javax.xml.XMLConstants

```
public final class XMLConstants
extends Object
```
Utility class to contain basic XML values as constants.

Since:

1.5

See Also:

Extensible Markup Language (XML) 1.1, Extensible Markup Language (XML) 1.0 (Second Edition), XML 1.0 Second Edition Specification Errata, Namespaces in XML 1.1, Namespaces in XML, XML Schema Part 1: Structures

Field Summary

Fields
Modifier and Type	Field	Description
`static String`	`ACCESS_EXTERNAL_DTD`	Property: accessExternalDTD
`static String`	`ACCESS_EXTERNAL_SCHEMA`	Property: accessExternalSchema
`static String`	`ACCESS_EXTERNAL_STYLESHEET`	Property: accessExternalStylesheet
`static String`	`DEFAULT_NS_PREFIX`	Prefix to use to represent the default XML Namespace.
`static String`	`FEATURE_SECURE_PROCESSING`	Feature for secure processing.
`static String`	`NULL_NS_URI`	Namespace URI to use to represent that there is no Namespace.
`static String`	`RELAXNG_NS_URI`	RELAX NG Namespace URI.
`static String`	`USE_CATALOG`	Feature: useCatalog
`static String`	`W3C_XML_SCHEMA_INSTANCE_NS_URI`	W3C XML Schema Instance Namespace URI.
`static String`	`W3C_XML_SCHEMA_NS_URI`	W3C XML Schema Namespace URI.
`static String`	`W3C_XPATH_DATATYPE_NS_URI`	W3C XPath Datatype Namespace URI.
`static String`	`XML_DTD_NS_URI`	XML Document Type Declaration Namespace URI as an arbitrary value.
`static String`	`XML_NS_PREFIX`	The official XML Namespace prefix.
`static String`	`XML_NS_URI`	The official XML Namespace name URI.
`static String`	`XMLNS_ATTRIBUTE`	The official XML attribute used for specifying XML Namespace declarations.
`static String`	`XMLNS_ATTRIBUTE_NS_URI`	The official XML attribute used for specifying XML Namespace declarations, `XMLConstants.XMLNS_ATTRIBUTE`, Namespace name URI.

Method Summary
- Methods declared in class java.lang.Object
  clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - NULL_NS_URI
```
public static final String NULL_NS_URI
```
    Namespace URI to use to represent that there is no Namespace.
    Defined by the Namespace specification to be "".
    
    See Also:
    
    Namespaces in XML, 5.2 Namespace Defaulting, Constant Field Values
  - DEFAULT_NS_PREFIX
```
public static final String DEFAULT_NS_PREFIX
```
    Prefix to use to represent the default XML Namespace.
    Defined by the XML specification to be "".
    
    See Also:
    
    Namespaces in XML, 3. Qualified Names, Constant Field Values
  - XML_NS_URI
```
public static final String XML_NS_URI
```
    The official XML Namespace name URI.
    Defined by the XML specification to be "http://www.w3.org/XML/1998/namespace".
    
    See Also:
    
    Namespaces in XML, 3. Qualified Names, Constant Field Values
  - XML_NS_PREFIX
```
public static final String XML_NS_PREFIX
```
    The official XML Namespace prefix.
    Defined by the XML specification to be "xml".
    
    See Also:
    
    Namespaces in XML, 3. Qualified Names, Constant Field Values
  - XMLNS_ATTRIBUTE_NS_URI
```
public static final String XMLNS_ATTRIBUTE_NS_URI
```
    The official XML attribute used for specifying XML Namespace declarations, XMLConstants.XMLNS_ATTRIBUTE, Namespace name URI.
    Defined by the XML specification to be "http://www.w3.org/2000/xmlns/".
    
    See Also:
    
    Namespaces in XML, 3. Qualified Names, Constant Field Values
  - XMLNS_ATTRIBUTE
```
public static final String XMLNS_ATTRIBUTE
```
    The official XML attribute used for specifying XML Namespace declarations.
    It is NOT valid to use as a prefix. Defined by the XML specification to be "xmlns".
    
    See Also:
    
    Namespaces in XML, 3. Qualified Names, Constant Field Values
  - W3C_XML_SCHEMA_NS_URI
```
public static final String W3C_XML_SCHEMA_NS_URI
```
    W3C XML Schema Namespace URI.
    Defined to be "http://www.w3.org/2001/XMLSchema".
    
    See Also:
    
    XML Schema Part 1: Structures, 2.6 Schema-Related Markup in Documents Being Validated, Constant Field Values
  - W3C_XML_SCHEMA_INSTANCE_NS_URI
```
public static final String W3C_XML_SCHEMA_INSTANCE_NS_URI
```
    W3C XML Schema Instance Namespace URI.
    Defined to be "http://www.w3.org/2001/XMLSchema-instance".
    
    See Also:
    
    XML Schema Part 1: Structures, 2.6 Schema-Related Markup in Documents Being Validated, Constant Field Values
  - W3C_XPATH_DATATYPE_NS_URI
```
public static final String W3C_XPATH_DATATYPE_NS_URI
```
    W3C XPath Datatype Namespace URI.
    Defined to be "http://www.w3.org/2003/11/xpath-datatypes".
    
    See Also:
    
    XQuery 1.0 and XPath 2.0 Data Model, Constant Field Values
  - XML_DTD_NS_URI
```
public static final String XML_DTD_NS_URI
```
    XML Document Type Declaration Namespace URI as an arbitrary value.
    Since not formally defined by any existing standard, arbitrarily define to be "http://www.w3.org/TR/REC-xml".
    
    See Also:
    
    Constant Field Values
  - RELAXNG_NS_URI
```
public static final String RELAXNG_NS_URI
```
    RELAX NG Namespace URI.
    Defined to be "http://relaxng.org/ns/structure/1.0".
    
    See Also:
    
    RELAX NG Specification, Constant Field Values
  - FEATURE_SECURE_PROCESSING
```
public static final String FEATURE_SECURE_PROCESSING
```
    Feature for secure processing.
    
    true instructs the implementation to process XML securely. This may set limits on XML constructs to avoid conditions such as denial of service attacks.
    
    false instructs the implementation to process XML in accordance with the XML specifications ignoring security issues such as limits on XML constructs to avoid conditions such as denial of service attacks.
    See Also:
    
    Constant Field Values
  - ACCESS_EXTERNAL_DTD
```
public static final String ACCESS_EXTERNAL_DTD
```
    Property: accessExternalDTD
    Restrict access to external DTDs and external Entity References to the protocols specified. If access is denied due to the restriction of this property, a runtime exception that is specific to the context is thrown. In the case of SAXParser for example, SAXException is thrown.
    
    Value: a list of protocols separated by comma. A protocol is the scheme portion of a URI, or in the case of the JAR protocol, "jar" plus the scheme portion separated by colon. A scheme is defined as:
    
    scheme = alpha *( alpha | digit | "+" | "-" | "." )
    where alpha = a-z and A-Z.
    
    And the JAR protocol:
    jar[:scheme]
    
    Protocols including the keyword "jar" are case-insensitive. Any whitespaces as defined by Character.isSpaceChar(char) in the value will be ignored. Examples of protocols are file, http, jar:file.
    
    Default value: The default value is implementation specific and therefore not specified. The following options are provided for consideration:
    
    an empty string to deny all access to external references;
    
    a specific protocol, such as file, to give permission to only the protocol;
    
    the keyword "all" to grant permission to all protocols.
    
    When FEATURE_SECURE_PROCESSING is enabled, it is recommended that implementations restrict external connections by default, though this may cause problems for applications that process XML/XSD/XSL with external references.
    
    Granting all access: the keyword "all" grants permission to all protocols.
    
    System Property: The value of this property can be set or overridden by system property javax.xml.accessExternalDTD.
    
    jaxp.properties: This configuration file is in standard Properties format and typically located in the conf directory of the Java installation. If the file exists and the system property is specified, its value will be used to override the default of the property.
    Since:
    
    1.7
    
    See Also:
    
    Constant Field Values
  - ACCESS_EXTERNAL_SCHEMA
```
public static final String ACCESS_EXTERNAL_SCHEMA
```
    Property: accessExternalSchema
    
    Restrict access to the protocols specified for external reference set by the schemaLocation attribute, Import and Include element. If access is denied due to the restriction of this property, a runtime exception that is specific to the context is thrown. In the case of SchemaFactory for example, org.xml.sax.SAXException is thrown.
    
    Value: a list of protocols separated by comma. A protocol is the scheme portion of a URI, or in the case of the JAR protocol, "jar" plus the scheme portion separated by colon. A scheme is defined as:
    
    scheme = alpha *( alpha | digit | "+" | "-" | "." )
    where alpha = a-z and A-Z.
    
    And the JAR protocol:
    jar[:scheme]
    
    Protocols including the keyword "jar" are case-insensitive. Any whitespaces as defined by Character.isSpaceChar(char) in the value will be ignored. Examples of protocols are file, http, jar:file.
    
    Default value: The default value is implementation specific and therefore not specified. The following options are provided for consideration:
    
    an empty string to deny all access to external references;
    
    a specific protocol, such as file, to give permission to only the protocol;
    
    the keyword "all" to grant permission to all protocols.
    
    When FEATURE_SECURE_PROCESSING is enabled, it is recommended that implementations restrict external connections by default, though this may cause problems for applications that process XML/XSD/XSL with external references.
    
    Granting all access: the keyword "all" grants permission to all protocols.
    
    System Property: The value of this property can be set or overridden by system property javax.xml.accessExternalSchema
    
    jaxp.properties: This configuration file is in standard Properties format and typically located in the conf directory of the Java installation. If the file exists and the system property is specified, its value will be used to override the default of the property.
    Since:
    
    1.7
    
    See Also:
    
    Constant Field Values
  - ACCESS_EXTERNAL_STYLESHEET
```
public static final String ACCESS_EXTERNAL_STYLESHEET
```
    Property: accessExternalStylesheet
    Restrict access to the protocols specified for external references set by the stylesheet processing instruction, Import and Include element, and document function. If access is denied due to the restriction of this property, a runtime exception that is specific to the context is thrown. In the case of constructing new Transformer for example, TransformerConfigurationException will be thrown by the TransformerFactory.
    
    Value: a list of protocols separated by comma. A protocol is the scheme portion of a URI, or in the case of the JAR protocol, "jar" plus the scheme portion separated by colon. A scheme is defined as:
    
    scheme = alpha *( alpha | digit | "+" | "-" | "." )
    where alpha = a-z and A-Z.
    
    And the JAR protocol:
    jar[:scheme]
    
    Protocols including the keyword "jar" are case-insensitive. Any whitespaces as defined by Character.isSpaceChar(char) in the value will be ignored. Examples of protocols are file, http, jar:file.
    
    Default value: The default value is implementation specific and therefore not specified. The following options are provided for consideration:
    
    an empty string to deny all access to external references;
    
    a specific protocol, such as file, to give permission to only the protocol;
    
    the keyword "all" to grant permission to all protocols.
    
    When FEATURE_SECURE_PROCESSING is enabled, it is recommended that implementations restrict external connections by default, though this may cause problems for applications that process XML/XSD/XSL with external references.
    
    Granting all access: the keyword "all" grants permission to all protocols.
    
    System Property: The value of this property can be set or overridden by system property javax.xml.accessExternalStylesheet
    
    jaxp.properties: This configuration file is in standard Properties format and typically located in the conf directory of the Java installation. If the file exists and the system property is specified, its value will be used to override the default of the property.
    Since:
    
    1.7
    
    See Also:
    
    Constant Field Values
  - USE_CATALOG
```
public static final String USE_CATALOG
```
    Feature: useCatalog
    Instructs XML processors to use XML Catalogs to resolve entity references. Catalogs may be set through JAXP factories, system properties, or jaxp.properties by using the javax.xml.catalog.files property defined in CatalogFeatures. The following code enables Catalog on SAX parser:
    
    SAXParserFactory spf = SAXParserFactory.newInstance(); spf.setFeature(XMLConstants.USE_CATALOG, true); SAXParser parser = spf.newSAXParser(); parser.setProperty(CatalogFeatures.Feature.FILES.getPropertyName(), "catalog.xml");
    
    Value: a boolean. If the value is true, and a catalog is set, the XML parser will resolve external references using CatalogResolver. If the value is false, XML Catalog is ignored even if one is set. The default value is true.
    
    System Property: The value of this property can be set or overridden by system property javax.xml.useCatalog
    
    jaxp.properties: This configuration file is in standard Properties format and typically located in the conf directory of the Java installation. If the file exists and the system property is specified, its value will be used to override the default value of the property.
    Since:
    
    9
    
    See Also:
    
    Constant Field Values

Java Module java.xml Package javax.xml Class XMLConstants（JDK11）

Class XMLConstants

Field Summary

Method Summary

Methods declared in class java.lang.Object

Field Detail

NULL_NS_URI

DEFAULT_NS_PREFIX

XML_NS_URI

XML_NS_PREFIX

XMLNS_ATTRIBUTE_NS_URI

XMLNS_ATTRIBUTE

W3C_XML_SCHEMA_NS_URI

W3C_XML_SCHEMA_INSTANCE_NS_URI

W3C_XPATH_DATATYPE_NS_URI

XML_DTD_NS_URI

RELAXNG_NS_URI

FEATURE_SECURE_PROCESSING

ACCESS_EXTERNAL_DTD

ACCESS_EXTERNAL_SCHEMA

ACCESS_EXTERNAL_STYLESHEET

USE_CATALOG