Factory class for creating an XMLReader. This factory tries to use the system property
'org.xml.sax.driver', if that fails it falls back on javax.xml.sax.parsers.SAXParserFactory. If the
SAXParserFactory class can not be found (this can happen when using a Java 1.3 or older), or the
initialization using SAXParserFactory fails otherwise, the factory falls back on the Xerces 2 SAX Parser.
creates an org.xml.sax.XMLReader object. The method first tries to create the XMLReader object
specified in the 'org.xml.sax.driver' system property. If that fails, it tries to use
java.xml.parsers.SAXParserFactory. If that also fails, it tries to initialize the Xerces 2 SAX parser.
If that also fails, a SAXException is thrown.
SAXException - when no default XMLReader class can be found or instantiated.