XMLparser: Difference between setValidating() and setFeature(.....validation) ???

[Markus Meckler]

What is the difference between

parser.setFeature("http://xml.org/sax/features/validation",true);
and
parser.setFeature("http://apache.org/xml/features/validation/schema",true);
and
parser.setValidating(true);

when I prepare a SAX/DOM parser for validation of an xml/xsd scheme

Marcus