changed the parameters "type" and "deviceId" as required for the last-know api.

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/api/DeviceEventManagementService.java

@@ -290,9 +290,9 @@ public interface DeviceEventManagementService {
                             response = ErrorResponse.class)
             }
     )
-    Response getLastKnownData(@ApiParam(name = "deviceId", value = "id of the device ", required = false)
+    Response getLastKnownData(@ApiParam(name = "deviceId", value = "id of the device ", required = true)
                               @PathParam("deviceId") String deviceId,
-                              @ApiParam(name = "type", value = "name of the device type", required = false)
+                              @ApiParam(name = "type", value = "name of the device type", required = true)
                               @PathParam("type") String deviceType,
                               @ApiParam(name = "limit", value = "limit of the records that needs to be picked up", required = false)
                               @QueryParam("limit") int limit);

components/device-mgt/org.wso2.carbon.device.mgt.api/src/main/java/org/wso2/carbon/device/mgt/jaxrs/service/impl/DeviceEventManagementServiceImpl.java

@@ -382,7 +382,7 @@ public class DeviceEventManagementServiceImpl implements DeviceEventManagementSe
 
     /**
      * Returns last known data points up to the limit if limit is specified. Otherwise returns last known data point.
-     * Limit need to be zero or positive.
+     * Limit parameter needs to be zero or positive.
      */
     @GET
     @Path("/last-known/{type}/{deviceId}")
@@ -411,8 +411,7 @@ public class DeviceEventManagementServiceImpl implements DeviceEventManagementSe
             } else if (limit > 0) {
                 EventRecords eventRecords = getAllEventsForDevice(sensorTableName, query, sortByFields, 0, limit);
                 return Response.status(Response.Status.OK.getStatusCode()).entity(eventRecords).build();
-            }
+            } else {
-            else{
                 String errorMessage = "Invalid limit value";
                 return Response.status(Response.Status.BAD_REQUEST).entity(errorMessage).build();
             }