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For this recipe, we didn't create any configuration class. But if you want to define the base URL for callback redirection that happens when using the OAuth 2.0 protocol, you need to create a configuration class to define a custom ConnectController bean, as presented in the following code:

@Configuration 
public class LinkedInConfiguration { 
    @Bean 
    public ConnectController connectController(ConnectionFactoryLocator locator, 
        ConnectionRepository repository) { 
        ConnectController controller = new ConnectController(locator, repository); 
        controller.setApplicationUrl("http://localhost:8080"); 
        return controller; 
    } 
} 

By doing such configurations, you avoid issues when the application runs behind a proxy. The redirect URI will be automatically generated using the request info which will be based on the application which might be running behind a proxy. This way, the OAuth 2.0 Provider won't be able to redirect to the right callback URL because it will be hidden by the proxy. The configuration presented previously allows you to define the proxy's URL.

Do not forget to define the same redirect URL at the OAuth 2.0 Provider and make all the communication through TLS/SSL.