Using nimbus oauth2 and spring-boot, getting a BeanCreationException with AuthorizationServerMetaData

Question

I have a spring boot application running on spring boot 2.7.18. For authentication purposes I am using the com.nimbusds.oauth2.sdk version 8.4.2.

I have an interface called AuthServiceAgent.

public interface CurityAuthServiceAgent {

    /**
     * Get the authorized {@link AuthId} given the supplied credentials.
     */
    Single<AuthId> getAuthorizedUser(String token);
...

}

The implementation of this interface looks like this:

@Component
@Lazy
@Qualifier("regular")
public class AuthServiceAgentImpl implements AuthServiceAgent {

    ...

    @Qualifier("CommonAsyncHttpExecutor")
    @Autowired
    private AsyncHttpExecutor asyncHttpExecutor;

    @Value("${auth.issuer-url}")
    private Issuer issuerUrl;

    @Value("${auth.scope}")
    private String requiredScope;

...

    @Lazy
    @Autowired
    private AuthorizationServerMetadata authorizationServerMetadata;

    @Bean
    @Lazy
    private AuthorizationServerMetadata authorizationServerMetadata() {
        return getAuthorizationServerMetadata().blockingGet();
    }

private Single<AuthorizationServerMetadata> getAuthorizationServerMetadata() {
    // Connect to auth server and fetch meta data (e.g. endpoint URIs)
    logger.info("Fetching authorization server metadata from {}", issuerUrl.getValue());
    var request = new OIDCProviderConfigurationRequest(issuerUrl);
    var httpRequest = request.toHTTPRequest();
    httpRequest.setEntityContentType(ContentType.APPLICATION_JSON);

    return asyncHttpExecutor.execute("getauthservermetadata", toAhcRequest(httpRequest)).map(response -> {
        HTTPResponse httpResponse = toHttpResponse(response);
        return OIDCProviderMetadata.parse(httpResponse.getContentAsJSONObject());
    });
}

    @Override
    public Single<AuthId> getAuthorizedUser(String token) {
//Error happens here
        TokenIntrospectionRequest request =
            new TokenIntrospectionRequest(authorizationServerMetadata.getIntrospectionEndpointURI(),
                clientAuthentication, new BearerAccessToken(token));
    ...

When I add a second implementation of the interface AuthServiceAgent

@Component
@Lazy
@Qualifier("other")
public class AuthServiceAgentImplOther implements AuthServiceAgent {

    @Qualifier("CommonAsyncHttpExecutor")
@Autowired
private AsyncHttpExecutor asyncHttpExecutor;

@Value("${auth.issuer-url-other}")
private Issuer issuerUrlZiklo;

@Value("${auth.scope}")
    private String requiredScope;

...

    @Lazy
@Autowired
private AuthorizationServerMetadata authorizationServerMetadata;


//The rest is the same as "regular" implementation

I get an error when attempting to perform a token introspection.

The error I get when debugging this line in the code

TokenIntrospectionRequest request = new TokenIntrospectionRequest(authorizationServerMetadata.getIntrospectionEndpointURI(),
                clientAuthentication, new BearerAccessToken(token));

is this

org.springframework.beans.factory.BeanCreationException' exception.
Cannot evaluate com.nimbusds.oauth2.sdk.as.AuthorizationServerMetadata$$EnhancerBySpringCGLIB$$fd62187.toString()

Removing either one of the implementations makes everything work nicely. A guess is that the application can't handle AuthorizationServerMetaData, but this is from the nimbus oauth2 library, and not my code. I am trying to find a way for another class to autowire and use either one of the implementations based on a condition.

@Component("MainAuthorizer")
@Lazy
public class Authorizer implements Authorizer<RequestContext> {

@Qualifier("regular")
@Autowired
private AuthServiceAgent serviceAgentRegular;

@Qualifier("other")
@Autowired
private AuthServiceAgent serviceAgentOther;
...

This works fine, until either one of the implementations need to do the introspection.