As jtahlborn points out, you should always treat XML as bytes, letting the parser work out the encoding.
But more than that, you should never ever use String.getBytes() to get the bytes of a string: you will not be getting what you think you are.
In this case you can just get the bytes of the site, but even if you were constructing XML in a string and then handing that to a parser as a byte sequence (or, more likely, writing the bytes to a file), you would want to specify the encoding such that it matches the encoding the XML says it's in, which by default is UTF-8:
byte[] bytes = myString.getBytes("UTF-8");
Likewise, if for some reason you needed to use a Writer or Reader, you must specify the encoding to write or read in.
If you need to construct XML, a good way is to use the XMLStreamWriter class:
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
XMLStreamWriter writer =
XMLOutputFactory.newInstance().createXMLStreamWriter(outStream);