problem with https://xxx

Hi all, 
I am using apache jar(XERCES.JAR) to parse an xml file coming through an
url. Normally It works fine(with <http://xxx.xml).> 
but when i pass the url(with https://xxx.xml) as a parameter to
docBuilder.parse(string url); then it throughs an exception saying file
not found. 
I would like to know is there anything extra we need to do to deal with
SECURED HTTP's? 
Thank you all, 
bye,
vamsi.