This task checks that XML files are valid (or only well formed). The task uses the SAX2 parser implementation provided by JAXP by default (probably the one that is used by Apache Ant itself), but one can specify any SAX1/2 parser if needed.

This task supports the use of nested

Warning: By default, JAXP creates a non namespace aware parser. The http://xml.org/sax/features/namespaces feature is set by default to false by the JAXP implementation used by Ant. To validate a document containing namespaces, set the namespaces feature to true explicitly by nesting the following element:

<attribute name="http://xml.org/sax/features/namespaces" value="true"/>

If you are using for instance a xsi:noNamespaceSchemaLocation attribute in your XML files, you will need this namespace support feature.

If you are using a parser not generated by JAXP, by using the classname attribute of xmlvalidate, this warning may not apply.


Attribute Description Required
file the file(s) you want to check. Yes, unless an embedded <fileset> is specified
lenient if true, only check the XML document is well formed (ignored if the specified parser is a SAX1 parser). No
classname the parser to use. No
classpathref where to find the parser class. No, can use an embedded <classpath> element
failonerror fails on a error if set to true. No; defaults to true
warn log parser warn events. No

Parameters specified as nested elements


<dtd> is used to specify different locations for DTD resolution.

Attribute Description Required
publicId Public ID of the DTD to resolve Yes
location Location of the DTD to use, which can be a file, a resource, or a URL Yes


The <xmlcatalog> element is used to perform entity resolution.


The <attribute> element is used to set parser features.

Features usable with the Xerces parser are defined here: Setting Features

SAX features are defined here: SAX2 Standard Feature Flags

Attribute Description Required
name The name of the feature Yes
value The boolean value of the feature Yes


The <property> element is used to set properties. These properties are defined here for the Xerces XML parser implementation: XML Parser properties. Properties can be used to set the schema used to validate the XML file.

Attribute Description Required
name The name of the feature Yes
value The string value of the property Yes


<xmlvalidate file="toto.xml"/>

Validate toto.xml

<xmlvalidate failonerror="no" lenient="yes" warn="yes"
  <fileset dir="src" includes="style/*.xsl"/>

Validate all .xsl files in src/style, but only warn if there is an error, rather than halt the build.

<xmlvalidate file="struts-config.xml" warn="false">
  <dtd publicId="-//Apache Software Foundation//DTD Struts Configuration 1.0//EN"

Validate a struts configuration, using a local copy of the DTD.

<xmlvalidate failonerror="no">
  <fileset dir="${project.dir}" includes="**/*.xml"/>
  <xmlcatalog refid="mycatalog"/>

Scan all XML files in the project, using a predefined catalog to map URIs to local files.

<xmlvalidate failonerror="no">
  <fileset dir="${project.dir}" includes="**/*.xml"/>
    <dtd publicId="-//ArielPartners//DTD XML Article V1.0//EN"

Scan all XML files in the project, using the catalog defined inline.

<xmlvalidate failonerror="yes" lenient="no" warn="yes">
  <fileset dir="xml" includes="**/*.xml"/>
  <attribute name="http://xml.org/sax/features/validation" value="true"/>
  <attribute name="http://apache.org/xml/features/validation/schema"  value="true"/>
  <attribute name="http://xml.org/sax/features/namespaces" value="true"/>

Validate all .xml files in xml directory with the parser configured to perform XSD validation. Note: The parser must support the feature http://apache.org/xml/features/validation/schema. The schemavalidate task is better for validating W3C XML Schemas, as it extends this task with the right options automatically enabled, and makes it easy to add a list of schema files/URLs to act as sources.

<!-- Convert path to URL format -->
<pathconvert dirsep="/" property="xsd.file">
   <pathelement location="xml/doc.xsd"/>

<xmlvalidate file="xml/endpiece-noSchema.xml" lenient="false" failonerror="true" warn="true">
  <attribute name="http://apache.org/xml/features/validation/schema" value="true"/>
  <attribute name="http://xml.org/sax/features/namespaces" value="true"/>
  <property name="http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation"

Validate the file xml/endpiece-noSchema.xml against the schema xml/doc.xsd.