Minor Description
The SyncopeLoginModule calls a REST service from Syncope to receive user and role information. The REST service is able to respond in XML or in JSON. The current SyncopeLoginModule implementation parses the Sycnope response and expects XML. (see extractingRoles method)
The client should sent the request for the XML content type. Something like this:
get.setHeader("Content-Type", "application/xml");
If Syncope sends JSON no roles could get processed.