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.