Although the terms REST Service and RESTful Web Service are often used interchangeably, there is a subtle distinction. A REST Service may expose APIs over HTTP, but a RESTful Web Service strictly follows REST architectural principles such as stateless communication, resource-based URIs, proper use of HTTP methods, and standardized responses. In practice, every RESTful service is a REST service, but not every REST service is truly RESTful.
Key Points: • RESTful Web Services strictly adhere to REST constraints such as statelessness, resource orientation, cacheability, and uniform interfaces. • A service that uses HTTP and JSON but ignores REST principles may be called a REST service, but it is not fully RESTful. • RESTful design improves scalability, maintainability, interoperability, and API consistency.
Example: A URL like:
GET /users/101
is RESTful because it represents a resource and uses the appropriate HTTP method.
Whereas:
GET /getUser?id=101
works as a service endpoint but is less aligned with RESTful resource-oriented design.
Code Example:
@RestController
@RequestMapping("/users")
public class UserController {
@GetMapping("/{id}")
public User getUser(
@PathVariable Long id) {
return userService.getUser(id);
}
}Interview Tip: A concise interview answer is: RESTful Web Services strictly follow REST principles such as statelessness, resource-based URIs, and proper HTTP method usage. A REST service may use HTTP for communication but may not fully comply with REST constraints. Therefore, RESTful services represent a more disciplined and standards-compliant implementation of REST.