@GET
  @Path("{groupId}")
  @Produces(MediaType.TEXT_PLAIN)
  @ApiOperation(value = "Returns a single config group", response = ConfigGroupResponse.ConfigGroupWrapper.class)
  @ApiImplicitParams({
    @ApiImplicitParam(name = QUERY_FIELDS, value = QUERY_FILTER_DESCRIPTION, defaultValue = "ConfigGroup/*", dataType = DATA_TYPE_STRING, paramType = PARAM_TYPE_QUERY),
  })
  @ApiResponses({
    @ApiResponse(code = HttpStatus.SC_OK, message = MSG_SUCCESSFUL_OPERATION),
    @ApiResponse(code = HttpStatus.SC_NOT_FOUND, message = MSG_CLUSTER_NOT_FOUND),
    @ApiResponse(code = HttpStatus.SC_UNAUTHORIZED, message = MSG_NOT_AUTHENTICATED),
    @ApiResponse(code = HttpStatus.SC_FORBIDDEN, message = MSG_PERMISSION_DENIED),
    @ApiResponse(code = HttpStatus.SC_INTERNAL_SERVER_ERROR, message = MSG_SERVER_ERROR),
    @ApiResponse(code = HttpStatus.SC_BAD_REQUEST, message = MSG_INVALID_ARGUMENTS),
  })
  public Response getConfigGroup(String body, @Context HttpHeaders headers,
          @Context UriInfo ui, @PathParam("groupId") String groupId) {
    return handleRequest(headers, body, ui, Request.Type.GET,
        createConfigGroupResource(m_clusterName, groupId));
  }
Handles URL: /clusters/{clusterId}/config_groups/{groupId}
Get details on a config group.

@return
ambari-server/src/main/java/org/apache/ambari/server/api/services/ConfigGroupService.java