List Of All Groups and Group is not Deleted

Following is the given API for List Of All Groups:
@GET
@Path(value="/")
public List<Group> get(@QueryParam(value="sid")
String sid)
Get the list of all groups

URL://group?sid=f724670a-5006-449e-8990-608637852a50

It will not work on Restlet (it will showing the 500 Error) and also it will not showing the list of all group present in OPenMeetings.

Following is the API for Deleting Group:
@DELETE
@Path(value="/

")
public ServiceResult delete(@QueryParam(value="sid")
String sid,
@PathParam(value="id")
long id)

URL: /group/13?sid=f724670a-5006-449e-8990-608637852a50

Group is not Deleted by Group ID.

What is the Requirement to solve this two isses.