XML-based language that describes and traces web services.

XML-based language that describes and traces web services.

• A. RESTful
• B. UDDI
• C. SOAP
• D. WSDL

Answer: (D)

An XML-based language that describes a web service's interface, including its operations, input and output messages, and how to access the service, is the Web Services Description Language. WSDL defines the contract between a provider and a consumer: the available operations (what you can do), the data structures involved (the messages), how those messages are formatted and transmitted (bindings and protocols), and where the service lives (endpoints). This makes it possible for client code to be generated automatically and for different systems to interoperate by agreeing on a standard description. RESTful is not a description language; it’s an architectural style focused on resources and HTTP methods, often with JSON. UDDI is a registry for discovering services, not the specification of how to interact with them. SOAP is a protocol for exchanging XML messages; it defines how requests and responses are carried, not the formal interface description itself.

An XML-based language that describes a web service's interface, including its operations, input and output messages, and how to access the service, is the Web Services Description Language. WSDL defines the contract between a provider and a consumer: the available operations (what you can do), the data structures involved (the messages), how those messages are formatted and transmitted (bindings and protocols), and where the service lives (endpoints). This makes it possible for client code to be generated automatically and for different systems to interoperate by agreeing on a standard description.

RESTful is not a description language; it’s an architectural style focused on resources and HTTP methods, often with JSON. UDDI is a registry for discovering services, not the specification of how to interact with them. SOAP is a protocol for exchanging XML messages; it defines how requests and responses are carried, not the formal interface description itself.