how to check if a response is in xml format instead of HTML?

Question

Im working with a server which always sends me XML responds. But sometimes when server is lack or something it reports me about it by sending me back a HTML page (it just a html page informing about the error) but i didn't expect that and my XML parser crashed.
Im using DefaultHttpClient() and I do send header like mHttpRequest.setHeader("Accept", "text/xml");
So what is the proper way to ensure i got XML (or other specific format) response?

Answer 1

As Kristian suggested, see if it provides a different Content-Type when HTML is emitted. Failing that I would check for a <?xml... line, as apposed to a doctype or whatever is on the HTML page.