I did try and build your code to run the test (I've no idea where the CsvParam and DateParam classes come from) but I think that the following will give you wha

I did try and build your code to run the test (I've no idea where the CsvParam and DateParam classes come from) but I think that the following will give you what you want without throwing the exception. @DELETE @Path("{uid: [0-9]+}") public Response deleteStudent(@PathParam("uid") int uid) { final Student deletedStudent = STUDENTS.remove(uid); if (deletedStudent == null) { return Response.status(Response.Status.NOT_FOUND).build(); } else { return Response.ok().entity(true).build(); } }