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REST Web Services Interview Questions Toggle navigation In28Minutes Download Java Interview Pdf Guide Popular Video Courses Buy Java Interview Video Guide - $12.99/₹799 Start learning on Udemy today! REST Web Services Interview Questions What is a REST Web Service? What are important constraints for a RESTful Web Service? What is Richardson Maturity Model? What are the weightier practices in designing RESTful APIs? What are the weightier practices in using HTTP methods with Restful Web Services? Can you explain a little bit well-nigh JAX-RS? What are the advantages of Restful web services? What is the difference between REST and SOAP Based Services? What is a REST Web Service? There are a set of architectural constraints (we will discuss them shortly) tabbed Rest Style Constraints. Any service which satisfies these constraints is tabbed RESTful Web Service. There are a lot of misconceptions well-nigh REST Web Services : They are over HTTP , based on JSON etc. Yes :Increasinglythan 90% of RESTful Web Services are JSON over HTTP. But these are not necessary constraints. We can have RESTful Web Services which are not using JSON and which are not over HTTP. What are important constraints for a RESTful Web Service? The five important constraints for RESTful Web Service areVendee- Server : There should be a service producer and a service consumer. The interface (URL) is uniform and exposing resources. Interface uses nouns (not actions) The service is stateless. Even if the service is tabbed 10 times, the result must be the same. The service result should be Cacheable. HTTP cache, for example. Service should seem a Layered architecture.Vendeeshould not seem uncontrived connection to server - it might be getting info from a middle layer - cache. What is Richardson Maturity Model? Richardson Maturity Model defines the maturity level of a Restful Web Service. Following are the variegated levels and their characteristics. Level 0 : Expose SOAP web services in REST style. Expose whoopee based services (http://server/getPosts, http://server/deletePosts, http://server/doThis, http://server/doThat etc) using REST. Level 1 : Expose Resources with proper URI’s (using nouns). Ex: http://server/accounts, http://server/accounts/10. However, HTTP Methods are not used. Level 2 : Resources use proper URI's + HTTP Methods. For example, to update an account, you do a PUT to . The create an account, you do a POST to . Uri’s squint like posts/1/comments/5 and accounts/1/friends/1. Level 3 : HATEOAS (Hypermedia as the engine of using state). You will tell not only well-nigh the information stuff requested but moreover well-nigh the next possible deportment that the service consumer can do. When requesting information well-nigh a facebook user, a REST service can return user details withal with information well-nigh how to get his recent posts, how to get his recent comments and how to retrieve his friend’s list. What are the weightier practices in designing RESTful APIs? While designing any API, the most important thing is to think well-nigh the api consumer i.e. the vendee who is going to use the service. What are his needs? Does the service uri make sense to him? Does the request, response format make sense to him? In Rest, we think Nouns (resources) and NOT Verbs (NOT actions). So, URI’s should represent resources. URI’s should be hierarchical and as self descriptive as possible. Prefer plurals. Always use HTTP Methods.Weightierpractices with respect to each HTTP method is described in the next question. What are the weightier practices in using HTTP methods with Restful Web Services? GET : Should not update anything. Should be idempotent (same result in multiple calls). Possible Return Codes 200 (OK) + 404 (NOT FOUND) +400 (BAD REQUEST) POST : Should create new resource. Ideally return JSON with link to newly created resource. Same return codes as get possible. In wing : Return lawmaking 201 (CREATED) is possible. PUT : Update a known resource. ex: update vendee details. Possible Return Codes : 200(OK) DELETE : Used to delete a resource. Can you explain a little bit well-nigh JAX-RS? JAX-RS is the JEE Specification for Restful web services implemented by all JEE compliant web servers (and using servers). Important Annotations: @ApplicationPath("/"). @Path("users") : used on matriculation and methods to pinpoint the url path. @GET @POST : Used to pinpoint the HTTP method that invokes the method. @Produces(MediaType.APPLICATION_JSON) : Defines the output format of Restful service. @Path("/{id}") on method (and) @PathParam("id") on method parameter : This helps in defining a dynamic parameter in Rest URL. @Path("{user_id}/followers/{follower_id}") is a increasingly complicated example. @QueryParam("page") : To pinpoint a method parameter ex: /users?page=10. Useful methods: Response.OK(jsonBuilder.build()).build() returns json response with status code. Json.createObjectBuilder(). add("id",user.getId()); creates a user object. What are the advantages of Restful web services? Lightweight : Easy to slosh from mobile devices also. Easy to expose : Little or no restrictions on output format and liaison protocol. Most Restful services use HTTP protocol : Entire web is based on HTTP and is built for efficiency of HTTP. Things like HTTP caching enable Restful services to be effective. High Performance : Less xml & soap overhead andIncreasinglycaching enable Restful services to be highly performant. What is the difference between REST and SOAP Based Services? First of all, REST is a set of architectural principles defining how a RESTful service should squint squint like. SOAP is a message mart format. SOAP defines the structure of message to exchanged. How should the header be? How should the request content be? So, there is no real comparison between REST and SOAP. To get a real comparison, I compare two popular implementation of these concepts. Restful Sample Implementation : JSON over HTTP SOAP Sample Implementation : XML over SOAP over HTTP All comparison is between the Sample Restful and SOAP implementations described above. REST is built over simple HTTP protocol. SOAP services are increasingly ramified to implement and increasingly ramified to consume. REST has largest performance and scalability. REST reads can be cached, SOAP based reads cannot be cached. REST permits many variegated data formats (JSON is the most popular choice) where as SOAP only permits XML. SOAP services have well specified structure and interface (WSDL). SOAP is based on well specified standards (WS-Security, WS-AtomicTransaction and WS-ReliableMessaging). If you loved these Questions, you will love our PDF Interview Guide with 400+ Questions. 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