The namespace of element 'Root' must be from the schema namespace, 'http://www.w3.org/2001/XMLSchema'?

Question

I have an xml document:

<?xml version="1.0" encoding="utf-8"?>
<Root>
  <Child name="MyType" compareMode="EQ"></Child>
</Root>

And I would like to validate this xml with help of the following xsd:

<?xml version="1.0" encoding="utf-8"?>
<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="Root">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="Child">
          <xs:complexType>
            <xs:attribute name="name" type="xs:string" use="required" />
            <xs:attribute name="compareMode" type="xs:string" use="required" />
          </xs:complexType>
        </xs:element>
      </xs:sequence>
    </xs:complexType>
  </xs:element>
</xs:schema>

When I try to validate it I receive the following error:

Exception in thread "main" org.xml.sax.SAXException: Validation failed against correct.xml. ErrorMessage:s4s-elt-schema-ns: The namespace of element 'Root' must be from the schema namespace, 'http://www.w3.org/2001/XMLSchema'.

My question is why Root has to be in the namespace of schema? Could that be that I validate the xml document not correctly?

public synchronized boolean isValid(String xmlFragment, File xmlSchema) throws SAXException, IOException{

// 1. Lookup a factory for the W3C XML Schema language

SchemaFactory factory = 
    SchemaFactory.newInstance("http://www.w3.org/2001/XMLSchema");

// 2. Compile the schema. 

Schema schema = factory.newSchema(xmlSchema);

// 3. Get a validator from the schema.
Validator validator = schema.newValidator();

// 4. Parse the document you want to check.
Source source = new StreamSource(new ByteArrayInputStream(xmlFragment.getBytes()));

// 5. Check the document    
    validator.validate(source);        
    return true;
}

Answer 1

Could it be that xmlSchema holds not the schema you have shown us, but the "schema for schema documents" published by W3C? The error message fragment "ErrorMessage:s4s-elt-schema-ns:" seems to hint at this.