NSURLSession Web service call in Objective c

Web service call in NSURLSession:

    NSString *URLString = [NSString stringWithFormat:@"Your URL"];

    //create a url object

    NSURL *url = [NSURL URLWithString:URLString];

    //create a configuration object for the session object

    NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];

    //start a new session with our previously created configuration

    NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration];

    //    / 2

    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];

    request.HTTPMethod = @"POST";

    

    //Parameter dictionary.

    NSDictionary *dictionary = @{@"DeviceUDID": @"836475-2C6E-4081-A04E-45689234682"};

    NSError *error = nil;

    NSData *data = [NSJSONSerialization dataWithJSONObject:dictionary

                                                   options:kNilOptions error:&error];

    if (!error)

    {

        NSURLSessionUploadTask *uploadTask = [session uploadTaskWithRequest:request fromData:data completionHandler:^(NSData *data,NSURLResponse *response,NSError *error)

        {

            // Handle response here

            if(error != nil)

            {

                NSLog(@"Error : %@", [error localizedDescription]);

            }

            else

            {

                NSString *responseString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

                NSLog(@"Result : %@", responseString);

            }

        }];

        [uploadTask resume];

    }