code: public Document parse(InputStream is)
          throws SAXException, IOException {
          if (is == null) {
              throw new IllegalArgumentException("InputStream cannot be null");
          }
  
          InputSource in = new InputSource(is);
          return parse(in);
      }
docs: Parse the content of the given <code>InputStream</code> as an XML
  document and return a new DOM {@link Document} object.
  An <code>IllegalArgumentException</code> is thrown if the
  <code>InputStream</code> is null.
  
  @param is InputStream containing the content to be parsed.
  @return <code>Document</code> result of parsing the
  <code>InputStream</code>
  @exception IOException If any IO errors occur.
  @exception SAXException If any parse errors occur.
  @see org.xml.sax.DocumentHandler