JSON parse error: Cannot deserialize instance of `java.lang.String` out of START_OBJECT token

[Gyurmatag]

Hi!

I have the fresh code base up and running with everything configured, but when I try to Log in or Sign up I get this error log:

org.springframework.http.converter.HttpMessageNotReadableException: An error occurred reading the OAuth 2.0 Error: JSON parse error: Cannot deserialize instance of java.lang.Stringout of START_OBJECT token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance ofjava.lang.Stringout of START_OBJECT token at [Source: (sun.net.www.protocol.http.HttpURLConnection$HttpInputStream); line: 1, column: 10] (through reference chain: java.util.LinkedHashMap["error"]); nested exception is org.springframework.http.converter.HttpMessageNotReadableException: JSON parse error: Cannot deserialize instance ofjava.lang.Stringout of START_OBJECT token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance ofjava.lang.String out of START_OBJECT token at [Source: (sun.net.www.protocol.http.HttpURLConnection$HttpInputStream); line: 1, column: 10] (through reference chain: java.util.LinkedHashMap["error"])

Maybe Facebook sending another format back and an update needed.
Hint: Google login/signup working fine...
Can you please fix this problem?

Thank you very much!

[ghassen1khalil]

I finally succeeded to resolve this problem thank's to @Grauzone's pull-request
You must add these methods in your SecurityConfig class :

private OAuth2UserService<OAuth2UserRequest, OAuth2User> oauth2UserService() {
        RestTemplate restTemplate = new RestTemplate();
        restTemplate.setErrorHandler(new OAuth2ErrorResponseErrorHandler());
        enhanceJsonMessageConverter(restTemplate);
        customOAuth2UserService.setRestOperations(restTemplate);
        return customOAuth2UserService;
    }

    private void enhanceJsonMessageConverter(RestTemplate restTemplate) {
        // NOTE:
        // Facebook's UserInfo API -> https://graph.facebook.com/me
        // returns "text/javascript; charset=UTF-8" for the "content-type" response header
        // even though the content is JSON. This is not correct and should be reported to Facebook to fix.
        //
        // This is a temporary workaround that adds "text/javascript; charset=UTF-8"
        // as a supported MediaType in MappingJackson2HttpMessageConverter,
        // which is used to convert the UserInfo response to a Map.

        HttpMessageConverter<?> jsonMessageConverter = restTemplate.getMessageConverters().stream()
                .filter(c -> c instanceof MappingJackson2HttpMessageConverter)
                .findFirst()
                .orElse(null);

        if (jsonMessageConverter == null) {
            return;
        }

        List<MediaType> supportedMediaTypes = new ArrayList<>(jsonMessageConverter.getSupportedMediaTypes());
        supportedMediaTypes.add(MediaType.valueOf("text/javascript;charset=UTF-8"));
        ((AbstractHttpMessageConverter) jsonMessageConverter).setSupportedMediaTypes(supportedMediaTypes);
    }

And then replace .userService(customOAuth2UserService) by .userService(oauth2UserService())