Answer by Daniel Nelson for Fatal Error :1:1: Content is not allowed in prolog

Looks like you forgot adding correct headers to your get request (ask the REST API developer or you specific API description):

HttpURLConnection connection = (HttpURLConnection)url.openConnection();connection.header("Accept", "application/xml")connection.setRequestMethod("GET");connection.connect();

or

connection.header("Accept", "application/xml;version=1")