Question

I have the following XML file:

<?xml version="1.0"?>
<!DOCTYPE library SYSTEM "library.dtd">
<library
xmlns="http://example.com/a"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://example.com library.xsd"
name=".NET Developer's Library">
<book>
<category>computerss</category>
<title>Programming Microsoft .NET</title>
<author>Jeff Prosise</author>
<isbn>0-7356-1376-1</isbn>
</book>
<book>
<category>computer</category>
<title>Microsoft .NET for Programmers</title>
<author>Fergal Grimes</author>
<isbn>1-930110-19-7</isbn>
</book>
</library>

And the following Java code:

DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
SchemaFactory sf = SchemaFactory.newInstance("http://www.w3.org/2001/XMLSchema");
docBuilderFactory.setSchema(sf.newSchema(new File("library.xsd")));
docBuilderFactory.setNamespaceAware(true);
DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
docBuilder.parse(new FileInputStream("data.xml"));

It produces the following error:

[Error] :7:33: cvc-elt.1: Cannot find the declaration of element 'library'.

If I remove the XSD declaration in the XML file everything works fine…

Any inside highly appreciated. Thanks.

And here is the schema:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="library">
        <xs:complexType>
            <xs:sequence>
                <xs:element ref="book" maxOccurs="unbounded"/>
            </xs:sequence>
            <xs:attribute name="name" type="xs:string" use="optional"/>
        </xs:complexType>
    </xs:element>
    <xs:element name="book">
        <xs:complexType>
            <xs:sequence>
                <xs:element ref="category"/>
                <xs:element ref="title"/>
                <xs:element ref="author"/>
                <xs:element ref="isbn"/>
            </xs:sequence>
        </xs:complexType>
    </xs:element>
    <xs:element  name="category">
    <xs:simpleType>
        <xs:restriction base="xs:string">
            <xs:enumeration value="computer" />
            <xs:enumeration value="poetry" />
        </xs:restriction>
    </xs:simpleType>
    </xs:element>
    <xs:element name="title" type="xs:string"/>
    <xs:element name="author" type="xs:string"/>
    <xs:element name="isbn" type="xs:string"/>
</xs:schema>

Answer 1

Your XML has a reference to namespace (xmlns=”http://example.com/a”) which is not the same as in your schema. Have you tried to validate your XML against schema in any XML editor (e.g. Altova or Eclipse etc).

So far it looks like your parsing error is legit, XML is not valid according to the schema.