Which method generates Apex callouts from WSDL?

The method that generates Apex callouts from WSDL is WSDL2Apex. This tool automates the process of creating Apex classes and methods based on a specified WSDL (Web Services Description Language) document. When you use WSDL2Apex, it parses the WSDL file, extracting the required information about the web service, such as operations and message formats, and then generates the corresponding Apex code to make callouts to the web service.

This approach allows developers to quickly integrate external SOAP web services into Salesforce by simplifying the process of creating the required infrastructure needed to communicate with those services. As a result, developers can focus on implementing business logic instead of dealing with the low-level details of web service communication.

Other integration methods listed are not focused on generating Apex callouts from WSDL directly. RESTful API integration, for instance, involves working with RESTful services, which do not require WSDL. SOAP-to-REST conversion refers to the process of transforming SOAP requests to RESTful requests but does not inherently create APEX callouts. Data Loader integration is primarily used for bulk data operations and does not involve the generation of callouts from a WSDL.