Module java.xml
The JAXP APIs
JAXP comprises a set of APIs built upon a number of XML technologies and standards that are essential for XML processing. These include APIs for:- Parsing: the
JAXP Parsing API
based onDocument Object Model (DOM)
andSimple API for XML Parsing (SAX)
, andStreaming API for XML (StAX)
; - Serializing: StAX and
Extensible Stylesheet Language Transformations (XSLT)
; - Validation: the
JAXP Validation API
based on the XML Schema Definition Language; - Transformation: the
JAXP Transformation API
or XSLT (Extensible Stylesheet Language Transformations); - Querying and traversing XML documents: the
XML XPath Language API (XPath)
; - Resolving external resources: the
XML Catalog API
;
Factories and Processors
Factories are the entry points of each API, providing methods to allow applications to set JAXP Properties programmatically, before creating processors. The Configuration section provides more details on this. Factories also support the JAXP Lookup Mechanism, in which applications can be deployed with third party implementations to use instead of JDK implementations
Processors are aggregates of parsers (or readers), serializers (or writers),
validators, and transformers that control and perform the processing in their
respective areas. They are defined in their relevant packages.
In the parsers
package for example,
are the DocumentBuilder
and
SAXParser
, that represent the DOM and
SAX processors.
The processors are configured and instantiated with their corresponding factories.
The DocumentBuilder and SAXParser for example are constructed with the
DocumentBuilderFactory
and SAXParserFactory
respectively.
Configuration
When a JAXP factory is invoked for the first time, it performs a configuration process to determine the implementation to be used and its subsequent behaviors. During configuration, the factory examines configuration sources such as the JAXP Properties, System Properties, and the JAXP Configuration File, and sets the values following the Property Precedence. The terminologies and process are defined below.JAXP Properties
JAXP properties are configuration settings that are applied to XML processors. They can be used to control and customize the behavior of a processor. Depending on the JAXP API that is being used, JAXP properties may be referred to as Attributes, Properties, or Features.System Properties
Select JAXP properties have corresponding System Properties allowing the properties to be set at runtime, on the command line, or within the JAXP Configuration File. For example, the System Propertyjavax.xml.catalog.resolve
may be used
to set the CatalogFeatures
' RESOLVE
property.
The exact time at which system properties are read is unspecified. In order to ensure that the desired values are properly applied, applications should ensure that system properties are set appropriately prior to the creation of the first JAXP factory and are not modified thereafter.
Configuration File
JAXP supports the use of configuration files for specifying the implementation class to load for the JAXP factories as well as for setting JAXP properties.
Configuration files are Java Properties
files that consist
of mappings between system properties and their values defined by various APIs
or processes. The following configuration file entries demonstrate setting the
javax.xml.parsers.DocumentBuilderFactory
and CatalogFeatures.RESOLVE
properties:
javax.xml.parsers.DocumentBuilderFactory=packagename.DocumentBuilderFactoryImpl
javax.xml.catalog.resolve=strict
jaxp.properties
File
By default, JAXP looks for the configuration file jaxp.properties
,
located in the ${java.home}/conf directory; and if the file exists, loads the
specified properties to customize the behavior of the XML factories and processors.
The jaxp.properties
file will be read only once during the initialization
of the JAXP implementation and cached in memory. If there is an error accessing
or reading the file, the configuration process proceeds as if the file does not exist.
User-defined Configuration File
In addition to thejaxp.properties
file, the system property
java.xml.config.file
can be set to specify the location of
a configuration file. If the java.xml.config.file
property is included
within a configuration file, it will be ignored.
When the java.xml.config.file
is specified, the configuration file will be
read and the included properties will override the same properties that were
defined in the jaxp.properties
file. If the java.xml.config.file
has not been set when the JAXP implementation is initialized, no further attempt
will be made to check for its existence.
The java.xml.config.file
value must contain a valid pathname
to a configuration file. If the pathname is not absolute, it will be considered
relative to the working directory of the JVM.
If there is an error reading the configuration file, the configuration process
proceeds as if the java.xml.config.file
property was not set.
Implementations may optionally issue a warning message.
Property Precedence
JAXP properties can be set in multiple ways, including by API methods, system properties, and the JAXP Configuration File. When not explicitly set, they will be initialized with default values or more restrictive values whenFEATURE_SECURE_PROCESSING
(FSP) is enabled. The configuration order of precedence for properties is as
follows, from highest to lowest:
The APIs for factories or processors
System Property
User-defined Configuration File
The default JAXP Configuration File
jaxp.properties
The default values for JAXP Properties. If the
FSP
is true, the default values will be set to process XML securely.
CatalogFeatures
' RESOLVE
property as an example, the following illustrates how these rules are applied:
Properties specified with factory or processor APIs have the highest precedence. The following code effectively sets the RESOLVE property to
strict
, regardless of settings in any other configuration sources.DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); dbf.setAttribute(CatalogFeatures.Feature.RESOLVE.getPropertyName(), "strict");
If the property is not set on the factory as in the above code, a system property setting will be in effect.
// in the following example, the RESOLVE property is set to 'continue' // for the entire application java -Djavax.xml.catalog.resolve=continue myApp
If the property is not set on the factory, or using a system property, the setting in a configuration file will take effect. The following entry sets the property to '
continue
'.javax.xml.catalog.resolve=continue
If the property is not set anywhere, it will be resolved to its default value that is '
strict
'.
JAXP Lookup Mechanism
JAXP defines an ordered lookup procedure to determine the implementation class to load for the JAXP factories. Factories that support the mechanism are listed in the table below along with the method, System Property, and System Default method to be used in the procedure.Factory | Method | System Property | System Default |
---|---|---|---|
DatatypeFactory
|
newInstance() |
javax.xml.datatype.DatatypeFactory |
newDefaultInstance() |
DocumentBuilderFactory
|
newInstance() |
javax.xml.parsers.DocumentBuilderFactory |
newDefaultInstance() |
SAXParserFactory
|
newInstance() |
javax.xml.parsers.SAXParserFactory |
newDefaultInstance() |
XMLEventFactory
|
newFactory() |
javax.xml.stream.XMLEventFactory |
newDefaultFactory() |
XMLInputFactory
|
newFactory() |
javax.xml.stream.XMLInputFactory |
newDefaultFactory() |
XMLOutputFactory
|
newFactory() |
javax.xml.stream.XMLOutputFactory |
newDefaultFactory() |
TransformerFactory
|
newInstance() |
javax.xml.transform.TransformerFactory |
newDefaultInstance() |
SchemaFactory
|
newInstance(schemaLanguage) |
javax.xml.validation.SchemaFactory: schemaLanguage[1] |
newDefaultInstance() |
XPathFactory
|
newInstance(uri) |
DEFAULT_PROPERTY_NAME + ":uri"[2] |
newDefaultInstance() |
newInstance(schemaLanguage)
method.
[2] where uri is the parameter to the
newInstance(uri)
method.
Lookup Procedure
The order of precedence for locating the implementation class of a JAXP Factory is as follows, from highest to lowest:- The system property as listed in the column System Property of the table JAXP Factories above
-
The service-provider loading facility, defined by the
ServiceLoader
class, to attempt to locate and load an implementation of the service using the default loading mechanism: the service-provider loading facility will use the current thread's context class loader to attempt to load the service. If the context class loader is null, the system class loader will be used.
In case of theSchemaFactory
SchemaFactory
, each potential service provider is required to implement the methodisSchemaLanguageSupported(String schemaLanguage)
. The first service provider found that supports the specified schema language is returned.
In case of theXPathFactory
XPathFactory
, each potential service provider is required to implement the methodisObjectModelSupported(String objectModel)
. The first service provider found that supports the specified object model is returned. -
Otherwise, the
system-default
implementation is returned, which is equivalent to calling thenewDefaultInstance() or newDefaultFactory()
method as shown in column System Default of the table JAXP Factories above.
In case of theSchemaFactory
SchemaFactory
, there must be a platform defaultSchemaFactory
for W3C XML Schema.
In case of theXPathFactory
XPathFactory
, there must be a platform defaultXPathFactory
for the W3C DOM, i.e.DEFAULT_OBJECT_MODEL_URI
.
- Implementation Note:
-
JDK built-in Catalog
The JDK has a built-in catalog that hosts DTDs and XSDs list in the following table.DTDs and XSDs in JDK built-in Catalog Source Files java.util.prefs.Preferences
preferences.dtd java.util.Properties
properties.dtd XML Schema Part 1: Structures Second Edition
XML Schema Part 2: Datatypes Second EditionXMLSchema.dtd
datatypes.dtd
XMLSchema.xsd
datatypes.xsdXHTML™ 1.0 The Extensible HyperText Markup Language xhtml1-frameset.dtd
xhtml1-strict.dtd
xhtml1-transitional.dtdXHTML™ 1.0 in XML Schema xhtml1-frameset.xsd
xhtml1-strict.xsd
xhtml1-transitional.xsdXHTML™ 1.1 - Module-based XHTML - Second Edition xhtml11.dtd XHTML 1.1 XML Schema Definition xhtml11.xsd XML DTD for W3C specifications xmlspec.dtd The "xml:" Namespace xml.xsd The catalog is loaded once when the first JAXP processor factory is created.
External Resource Resolution Process with the built-in Catalog
The JDK creates aCatalogResolver
with the built-in catalog when needed. This CatalogResolver is used as the default external resource resolver.XML processors may use resolvers (such as
EntityResolver
,XMLResolver
, andCatalogResolver
) to handle external references. In the absence of the user-defined resolvers, the JDK XML processors fall back to the default CatalogResolver to attempt to find a resolution before making a connection to fetch the resources. The fall-back also takes place if a user-defined resolver exists but allows the process to continue when unable to resolve the resource.If the default CatalogResolver is unable to locate a resource, it may signal the XML processors to continue processing, or skip the resource, or throw a CatalogException. The behavior is configured with the
jdk.xml.jdkcatalog.resolve
property.Implementation Specific Properties
In addition to the standard JAXP Properties, the JDK implementation supports a number of implementation specific properties whose name is prefixed by "jdk.xml.
". These properties also follow the configuration process as defined in the Configuration section.Refer to the Implementation Specific Properties table for the list of properties supported by the JDK implementation.
Processor Support
The properties may be supported by one or more processors as listed in the table below. Depending on the type of the property, they may be set via Method 1: setAttribute/Parameter/Property or 2: setFeature as illustrated in the relevant columns.Processors ID Name Method 1: setAttribute/Parameter/Property Method 2: setFeature DOM DOM Parser DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setAttribute(name, value);
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setFeature(name, value);
SAX SAX Parser SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser parser = spf.newSAXParser();
parser.setProperty(name, value);
SAXParserFactory spf = SAXParserFactory.newInstance();
spf.setFeature(name, value);
StAX StAX Parser XMLInputFactory xif = XMLInputFactory.newInstance();
xif.setProperty(name, value);
XMLInputFactory xif = XMLInputFactory.newInstance();
xif.setProperty(name, value);
Validation XML Validation API SchemaFactory schemaFactory = SchemaFactory.newInstance(schemaLanguage);
schemaFactory.setProperty(name, value);
SchemaFactory schemaFactory = SchemaFactory.newInstance(schemaLanguage);
schemaFactory.setFeature(name, value);
Transform XML Transform API TransformerFactory factory = TransformerFactory.newInstance();
factory.setAttribute(name, value);
TransformerFactory factory = TransformerFactory.newInstance();
factory.setFeature(name, value);
XSLTC Serializer XSLTC Serializer Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(name, value);
DOMLS DOM Load and Save LSSerializer serializer = domImplementation.createLSSerializer();
serializer.getDomConfig().setParameter(name, value);
XPath XPath XPathFactory factory = XPathFactory.newInstance();
factory.setProperty(name, value);
XPathFactory factory = XPathFactory.newInstance();
factory.setFeature(name, value);
Implementation Specific Properties Full Name (prefix jdk.xml.
) [1]Description System Property [2] Value [3] Security [4] Supported Processor [5] Since [6] Type Value Default Enforced ID Set Method jdk.xml.entityExpansionLimit
Limits the number of entity expansions. yes Integer A positive integer. A value less than or equal to 0 indicates no limit. If the value is not an integer, a NumberFormatException is thrown. 2500 2500 Yes DOM
SAX
StAX
Validation
TransformMethod 1 8 jdk.xml.elementAttributeLimit
Limits the number of attributes an element can have. 200 200 jdk.xml.maxOccurLimit
Limits the number of content model nodes that may be created when building a grammar for a W3C XML Schema that contains maxOccurs attributes with values other than "unbounded". 5000 5000 jdk.xml.totalEntitySizeLimit
Limits the total size of all entities that include general and parameter entities. The size is calculated as an aggregation of all entities. 100000 100000 jdk.xml.maxGeneralEntitySizeLimit
Limits the maximum size of any general entities. 100000 100000 jdk.xml.maxParameterEntitySizeLimit
Limits the maximum size of any parameter entities, including the result of nesting multiple parameter entities. 15000 15000 jdk.xml.entityReplacementLimit
Limits the total number of nodes in all entity references. 100000 100000 jdk.xml.maxElementDepth
Limits the maximum element depth. 100 100 jdk.xml.maxXMLNameLimit
Limits the maximum size of XML names, including element name, attribute name and namespace prefix and URI. 1000 1000 jdk.xml.isStandalone
Indicates that the serializer should treat the output as a standalone document. The property can be used to ensure a newline is written after the XML declaration. Unlike the property xml-declaration
, this property does not have an effect on whether an XML declaration should be written out.boolean true/false false N/A No DOMLS 17 jdk.xml.xsltcIsStandalone
Indicates that the XSLTC serializer should treat the output as a standalone document. The property can be used to ensure a newline is written after the XML declaration. Unlike the property OMIT_XML_DECLARATION
, this property does not have an effect on whether an XML declaration should be written out.This property behaves similar to that for DOMLS above, except that it is for the XSLTC Serializer and its value is a String.
String yes/no no N/A No XSLTC Serializer 17 jdk.xml.cdataChunkSize
Instructs the parser to return the data in a CData section in a single chunk when the property is zero or unspecified, or in multiple chunks when it is greater than zero. The parser shall split the data by linebreaks, and any chunks that are larger than the specified size to ones that are equal to or smaller than the size. yes Integer A positive integer. A value less than or equal to 0 indicates that the property is not specified. If the value is not an integer, a NumberFormatException is thrown. 0 N/A No SAX
StAX9 jdk.xml.extensionClassLoader Sets a non-null ClassLoader instance to be used for loading XSLTC java extension functions. no Object A reference to a ClassLoader object. Null if the value is not specified. null N/A No Transform 9 jdk.xml.xpathExprGrpLimit Limits the number of groups an XPath expression can contain. yes Integer A positive integer. A value less than or equal to 0 indicates no limit. If the value is not an integer, a NumberFormatException is thrown. 10 10 Yes Transform
XPath19 jdk.xml.xpathExprOpLimit Limits the number of operators an XPath expression can contain. 100 100 jdk.xml.xpathTotalOpLimit Limits the total number of XPath operators in an XSL Stylesheet. 10000 10000 Transform
jdk.xml.enableExtensionFunctions
Determines if XSLT and XPath extension functions are to be allowed. yes Boolean true or false. True indicates that extension functions are allowed; False otherwise. true false Yes Transform
XPathMethod 2 8 jdk.xml.overrideDefaultParser
Enables the use of a 3rd party's parser implementation to override the system-default parser for the JDK's Transform, Validation and XPath implementations. true or false. True enables the use of 3rd party's parser implementations to override the system-default implementation during XML Transform, Validation or XPath operation. False disables the use of 3rd party's parser implementations. false false Yes Transform
Validation
XPathMethod 2 9 jdk.xml.resetSymbolTable
Instructs the parser to reset its internal symbol table during each parse operation. true or false. True indicates that the SymbolTable associated with a parser needs to be reallocated during each parse operation.
False indicates that the parser's SymbolTable instance shall be reused during subsequent parse operations.false N/A No SAX Method 2 9 jdk.xml.dtd.support
[7]Instructs the parser to handle DTDs in accordance with the setting of this property. The options are: allow
-- indicates that the parser shall continue processing DTDs;ignore
-- indicates that the parser shall skip DTDs;deny
-- indicates that the parser shall reject DTDs as an error. The parser shall report the error in accordance with its relevant specification.
String allow, ignore, and deny
. Values are case-insensitive.allow No Yes DOM
SAX
StAX
Validation
TransformMethod 1 22 jdk.xml.jdkcatalog.resolve
Instructs the JDK default CatalogResolver to act in accordance with the setting of this property when unable to resolve an external reference with the built-in Catalog. The options are: continue
-- Indicates that the processing should continueignore
-- Indicates that the reference is skippedstrict
-- Indicates that the resolver should throw a CatalogException
String continue, ignore, and strict
. Values are case-insensitive.continue No Yes DOM
SAX
StAX
Validation
TransformMethod 1 22 [1] The full name of a property should be used to set the property.
[2] A value "yes" indicates there is a corresponding System Property for the property, "no" otherwise. The name of the System Property is the same as that of the property.
[3] The value must be exactly as listed in this table, case-sensitive. The value of the corresponding System Property is the String representation of the property value. If the type is boolean, the system property is true only if it is "true"; If the type is String, the system property is true only if it is exactly the same string representing the positive value (e.g. "yes" for
xsltcIsStandalone
); The system property is false otherwise. If the type is Integer, the value of the System Property is the String representation of the value (e.g. "64000" forentityExpansionLimit
).[4] A value "yes" indicates the property is a Security Property. As indicated in the Property Precedence, the values listed in the column
enforced
will be used to initialize these properties whenFSP
is true.[5] One or more processors that support the property. The IDs and Set Method are as shown in the table Processors.
[6] Indicates the initial release the property is introduced.
[7] The
jdk.xml.dtd.support
property complements the two existing DTD-related properties,disallow-doctype-decl
(fully qualified name:http://apache.org/xml/features/disallow-doctype-decl
) and supportDTD (javax.xml.stream.supportDTD
), by providing a uniformed support for the processors listed and a system property that can be used in the JAXP Configuration File. Whendisallow-doctype-decl
is set on the DOM or SAX factory, or supportDTD on StAX factory, thejdk.xml.dtd.support
property will have no effect.These three properties control whether DTDs as a whole shall be processed. When they are set to deny or ignore, other properties that regulate a part or an aspect of DTD shall have no effect.
Legacy Property Names (deprecated)
JDK releases prior to JDK 17 support the use of URI style prefix for properties. These legacy property names are deprecated as of JDK 17 and may be removed in future releases. If both new and legacy properties are set, the new property names take precedence regardless of how and where they are set. The overriding order as defined in Property Precedence thus becomes:- Value set on factories or processors using new property names.
- Value set on factories or processors using legacy property names;
- Value set as System Property;
- Value set in the configuration file;
- Value set by FEATURE_SECURE_PROCESSING;
- The default value;
The following table lists the properties and their corresponding legacy names.
Legacy Property Names (deprecated since 17) Property Legacy Property Name(s) jdk.xml.entityExpansionLimit
http://www.oracle.com/xml/jaxp/properties/entityExpansionLimit
jdk.xml.elementAttributeLimit
http://www.oracle.com/xml/jaxp/properties/elementAttributeLimit
jdk.xml.maxOccurLimit
http://www.oracle.com/xml/jaxp/properties/maxOccurLimit
jdk.xml.totalEntitySizeLimit
http://www.oracle.com/xml/jaxp/properties/totalEntitySizeLimit
jdk.xml.maxGeneralEntitySizeLimit
http://www.oracle.com/xml/jaxp/properties/maxGeneralEntitySizeLimit
jdk.xml.maxParameterEntitySizeLimit
http://www.oracle.com/xml/jaxp/properties/maxParameterEntitySizeLimit
jdk.xml.entityReplacementLimit
http://www.oracle.com/xml/jaxp/properties/entityReplacementLimit
jdk.xml.maxElementDepth
http://www.oracle.com/xml/jaxp/properties/maxElementDepth
jdk.xml.maxXMLNameLimit
http://www.oracle.com/xml/jaxp/properties/maxXMLNameLimit
jdk.xml.isStandalone
http://www.oracle.com/xml/jaxp/properties/isStandalone
jdk.xml.xsltcIsStandalone
http://www.oracle.com/xml/is-standalone
http://www.oracle.com/xml/jaxp/properties/xsltcIsStandalone
jdk.xml.extensionClassLoader
jdk.xml.transform.extensionClassLoader
jdk.xml.enableExtensionFunctions
http://www.oracle.com/xml/jaxp/properties/enableExtensionFunctions
- Module Graph:
- Since:
- 9
-
Packages
PackageDescriptionDefines constants for XML processing.Provides the classes for implementing XML Catalogs OASIS Standard V1.1, 7 October 2005.Defines XML/Java Type Mappings.Defines XML Namespace processing.Provides the classes for processing XML documents with a SAX (Simple API for XML) parser or a DOM (Document Object Model) Document builder.Defines interfaces and classes for the Streaming API for XML (StAX).Defines event interfaces for the Streaming API for XML (StAX).Provides utility classes for the Streaming API for XML (StAX).Defines the generic APIs for processing transformation instructions, and performing a transformation from source to result.Provides DOM specific transformation classes.Provides SAX specific transformation classes.Provides StAX specific transformation classes.Provides stream and URI specific transformation classes.Provides an API for validation of XML documents.Provides an object-model neutral API for the evaluation of XPath expressions and access to the evaluation environment.Provides the interfaces for the Document Object Model (DOM).Provides a factory for obtaining instances ofDOMImplementation
.Provides interfaces for DOM Level 2 Events.Provides interfaces for DOM Level 3 Load and Save.Provides interfaces for DOM Level 2 Range.Provides interfaces for DOM Level 2 Traversal.Provides interfaces for DOM Level 2 Views.Provides the interfaces for the Simple API for XML (SAX).Provides interfaces to SAX2 facilities that conformant SAX drivers won't necessarily support.Provides helper classes, including support for bootstrapping SAX-based applications. -
Services
TypeDescriptionFactory that creates newjavax.xml.datatype
Object
s that map XML to/from JavaObject
s.Defines a factory API that enables applications to obtain a parser that produces DOM object trees from XML documents.Defines a factory API that enables applications to configure and obtain a SAX based parser to parse XML documents.Factory that createsSchema
objects.A TransformerFactory instance can be used to createTransformer
andTemplates
objects.This interface defines a utility class for creating instances of XMLEventsDefines an abstract implementation of a factory for getting streams.Defines an abstract implementation of a factory for getting XMLEventWriters and XMLStreamWriters.Interface for reading an XML document using callbacks.AnXPathFactory
instance can be used to createXPath
objects.