What are the core classes used for HTTP callouts in Salesforce?

The core classes used for HTTP callouts in Salesforce are indeed Http, HttpRequest, and HttpResponse. These classes facilitate the process of making HTTP requests to external systems and handling the responses received from those systems.

The HttpRequest class is designed to construct the HTTP request, allowing developers to specify various parameters, such as the endpoint URL, HTTP method (GET, POST, etc.), headers, and body content. It is essential for defining what action needs to be taken when interacting with an external web service.

The HttpResponse class is utilized to capture and process the response received from the external service after the callout has been made. This class provides methods to access the status code, headers, and body content of the HTTP response, enabling developers to handle the response appropriately within their Salesforce applications.

The Http class acts as the overall controller for executing the callout process. It provides methods for sending the HttpRequest and returning the HttpResponse, thus allowing seamless communication between Salesforce and external web services.

Understanding these core classes is fundamental for any Salesforce Integration Architect, as they are routinely used to implement integration solutions that require communication with third-party services.