anchor.diff:  TIP: Spring MVC `FormHttpMessageConverter` is required as it's used when sending the OAuth 2.0 Access Token Request.
   
   `OAuth2AccessTokenResponseHttpMessageConverter` is a `HttpMessageConverter` for an OAuth 2.0 Access Token Response.
  -You can provide `OAuth2AccessTokenResponseHttpMessageConverter.setTokenResponseConverter()` with a custom `Converter<Map<String, String>, OAuth2AccessTokenResponse>` that is used for converting the OAuth 2.0 Access Token Response parameters to an `OAuth2AccessTokenResponse`.
  +You can provide `OAuth2AccessTokenResponseHttpMessageConverter.setAccessTokenResponseConverter()` with a custom `Converter<Map<String, Object>, OAuth2AccessTokenResponse>` that is used for converting the OAuth 2.0 Access Token Response parameters to an `OAuth2AccessTokenResponse`.
   
   `OAuth2ErrorResponseErrorHandler` is a `ResponseErrorHandler` that can handle an OAuth 2.0 Error, eg. 400 Bad Request.
   It uses an `OAuth2ErrorHttpMessageConverter` for converting the OAuth 2.0 Error parameters to an `OAuth2Error`.
  
positive.code: TIP: Spring MVC `FormHttpMessageConverter` is required as it's used when sending the OAuth 2.0 Access Token Request.
  
  `OAuth2AccessTokenResponseHttpMessageConverter` is a `HttpMessageConverter` for an OAuth 2.0 Access Token Response.
  You can provide `OAuth2AccessTokenResponseHttpMessageConverter.setTokenResponseConverter()` with a custom `Converter<Map<String, String>, OAuth2AccessTokenResponse>` that is used for converting the OAuth 2.0 Access Token Response parameters to an `OAuth2AccessTokenResponse`.
  
  `OAuth2ErrorResponseErrorHandler` is a `ResponseErrorHandler` that can handle an OAuth 2.0 Error, eg. 400 Bad Request.
  It uses an `OAuth2ErrorHttpMessageConverter` for converting the OAuth 2.0 Error parameters to an `OAuth2Error`.
  
negative.code: TIP: Spring MVC `FormHttpMessageConverter` is required as it's used when sending the OAuth 2.0 Access Token Request.
  
  `OAuth2AccessTokenResponseHttpMessageConverter` is a `HttpMessageConverter` for an OAuth 2.0 Access Token Response.
  You can provide `OAuth2AccessTokenResponseHttpMessageConverter.setAccessTokenResponseConverter()` with a custom `Converter<Map<String, Object>, OAuth2AccessTokenResponse>` that is used for converting the OAuth 2.0 Access Token Response parameters to an `OAuth2AccessTokenResponse`.
  
  `OAuth2ErrorResponseErrorHandler` is a `ResponseErrorHandler` that can handle an OAuth 2.0 Error, eg. 400 Bad Request.
  It uses an `OAuth2ErrorHttpMessageConverter` for converting the OAuth 2.0 Error parameters to an `OAuth2Error`.
  