<?xml version='1.0' encoding='UTF-8'?>
<article version="5.0" xml:lang="en"
  xmlns="http://docbook.org/ns/docbook"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xsi:schemaLocation="
    http://docbook.org/ns/docbook http://docbook.org/xml/5.0/xsd/docbook.xsd">
    <title>Sample article</title>
    <para>This is a very short article.</para>
</article>

XML validation started.
Checking file:/C:/sample_article.xml...
Referenced entity at "http://docbook.org/xml/5.0/xsd/docbook.xsd".
Referenced entity at "http://docbook.org/xml/5.0/xsd/xlink.xsd".
Referenced entity at "nbres:/org/netbeans/modules/j2ee/ddloaders/catalog/resources/XMLSchema.dtd".
Referenced entity at "nbres:/org/netbeans/modules/j2ee/ddloaders/catalog/resources/datatypes.dtd".
src-resolve: Cannot resolve the name 'xml:id' to a(n) 'attribute declaration' component. [6] http://docbook.org/xml/5.0/xsd/docbook.xsd
s4s-elt-must-match.1: The content of 'db.common.attributes' must match (annotation?, ((attribute | attributeGroup)*, anyAttribute?)). A problem was found starting at: attribute. [6] http://docbook.org/xml/5.0/xsd/docbook.xsd
cvc-complex-type.3.2.2: Attribute 'version' is not allowed to appear in element 'article'. [6]
cvc-complex-type.3.2.2: Attribute 'xml:lang' is not allowed to appear in element 'article'. [6]
XML validation finished.