performce issues between XMLReader and SAXParser

[Pieter van der Spek]

I've written a small validating parser using the Xerces SAX parser.
However, I have found a performance problem between to similar implementations.
The code for both is shown below:

public static void validate(String instance)
  {
    try
    {
      XMLReader parser= null;
      SAXParser parser2= new SAXParser();

      try {
        parser= XMLReaderFactory.createXMLReader(
          "org.apache.xerces.parsers.SAXParser"
        );
      } catch(SAXException se) {
        parser= XMLReaderFactory.createXMLReader();
        System.out.println("oops");
      }

      //Validate the document and report validity errors.
      parser.setFeature("http://xml.org/sax/features/validation";, true);
      parser2.setFeature("http://xml.org/sax/features/validation";, true);

      //Turn on XML Schema validation by inserting XML Schema
      // validator in the pipeline.
      parser.setFeature(
        "http://apache.org/xml/features/validation/schema";, true
      );
      parser2.setFeature(
            "http://apache.org/xml/features/validation/schema";, true
          );

      //Set the external schema location.
      parser.setProperty(
        
"http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation";,
        "file:///myschema.xsd"
      );
      parser2.setProperty(
            
"http://apache.org/xml/properties/schema/external-noNamespaceSchemaLocation";,
            "file:///myschema.xsd"
          );

      ErrorHandler errors = new ErrorHandler();
      parser.setErrorHandler(errors);
      parser2.setErrorHandler(errors);

      //Parse an XML document
      System.out.println("XMLReader:");
      System.out.println("Start: "+System.currentTimeMillis());
      parser.parse(instance);
      System.out.println("End: "+System.currentTimeMillis());
      System.out.println("-------");
      System.out.println("SAXParser:");
      System.out.println("Start: "+System.currentTimeMillis());
      parser2.parse(instance);
      System.out.println("End: "+System.currentTimeMillis());

      if (!errors.errorSeen())
      {
        System.out.println("Sucessfully validated " + instance);
      }
    }
    catch (Exception e)
    {
      System.out.print("Problem parsing the file:");
      System.out.println(e.getMessage());
      e.printStackTrace();
    }

The output from the four calls to System.currentTimeMillis() is the following
(this can vary from time to time of course):
XMLReader:
Start: 1084970176879
End: 1084970181622
-------
SAXParser:
Start: 1084970181625
End: 1084970182964


This tells me that the SAXParser takes 1339 milliseconds to complete while the
XMLReader takes 4743 milliseconds to complete!
What causes this difference. I expected both implementations to be
approximately as fast.
I hope someone can clear this up for me.
Thanks in advance.

Greetings,
Pieter van der Spek



                                   @ @
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Pieter van der Spek
---- West Consulting B.V.        - www.west.nl
---- Tu Delft / Computer Science - www.tudelft.nl

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