Optional SAX2 handler for lexical events.
This handler is used to obtain lexical information about an XML
document, that is, information about how the document was encoded
(as opposed to what it contains, which is reported to the
ContentHandler), such as comments and CDATA marked section
boundaries.
To set the LexicalHandler of an XMLReader, use the setProperty
method with the property identifier
'http://xml.org/sax/properties/lexical-handler'.