Top 55+ Web Services Interview Questions & Answers 2021
Are you looking to get a job as a Programmer? Maybe, a web service job? If you are aspiring to get a web service job, you would most probably need to fight an Interview. Appearing for an interview without any preparation is a sure-fire way to get rejected.
You must go well prepared in any Interview, but if you are contending for a Programming job, then it becomes crucial to be well prepared. Just because there is so much competition and you can’t take any risk. It is a good idea to sharpen your knowledge and revise old stuff before you face the interviewer.
In this article, I am going to list a lot of questions that are often asked in a Web services Job interview. If you do read these questions carefully, you would have a higher chance of getting selected. You can try to clear the underlying concept on the go if you feel stuck on any question.
Reading these questions once would bolster your confidence, and you will be all set to mix eyes with the interviewer. So without any ado, let’s grapple with the questions.
Let’s start with a fundamental question and then move on to advance ones. If you appear for a web services interview, then you must know the below question:
In this article, I am going to list a lot of questions that are often asked in a Web services Job interview. If you do read these questions carefully, you would have a higher chance of getting selected. You can try to clear the underlying concept on the go if you feel stuck on any question.
Reading these questions once would bolster your confidence, and you will be all set to mix eyes with the interviewer. So without any ado, let’s grapple with the questions.
Let’s start with a fundamental question and then move on to advance ones. If you appear for a web services interview, then you must know the below question:
1. What exactly is Web services?
A web service in layman’s terms is a software designed to facilitate communication between two machines or components over a network.
It exchanges information over HTTP protocol and makes use of SOAP to expose XML based protocol that makes two components able to communicate.
You can think of it as a Client-server system using the HTTP protocol to communicate and use SOAP to expose functionality.
2. What are the different types of Web Services?
Web services can be categorized into two types, as follows:
Restful web services
SOAP
3. What is SOAP?
SOAP is the shortened form of Simple object access protocol. It is a kind of contract that works on request and response model in XML format.
It is used to transmit information in XML format over HTTP, SMTP, or other protocols.
4. List some of the features of web services?
- Some of the features of Web services are-
- It enables us to exchange information over the internet.
- It enables us to use Old functionality into newer applications.
- Web services Are Extensible.
- They are loosely coupled.
5. What does Endpoint Refer to in SOAP?
End Point is the URL through which the Application or software data can be accessed.
6. What is the main difference between SOAP and restful web services?
The critical difference between the two is:
SOAP is the standard protocol utilized to design web services, whereas Restful is an architectural style to create web services. In SOAP, client and server are contract-Bonded while there is no such contract in Rest Protocol. Moreover, SOAP supports only XML format, and Restful architecture could support multiple formats like plain text, XML, and JSON.
7. How can we test SOAP web services?
To test SOAP web services, we can make use of SOAPUI.
8. How can one test Rest Web services?
Restful Web services could be tested using Postman for Chrome. If one wishes to check on Firefox, he could make use of Poster.
9. What components does SOAP use?
Some components that SOAP uses are as follows:
- Web Services Description Language (WSDL)
- Simple access object protocol (SOAP)
- Universal Description, Discovery, and Integration(UDDI).
10. What protocols does Web service make use of?
Web service uses a variety of protocols to operate and execute. These protocols form the web service protocol stack.
It includes- Service Transport, XML Messaging, Service Description, and Service Discovery.
11. Explain the Service Transport web service protocol?
The service transport protocol is responsible for transferring information or message via HTTP, SMTP, FTP, and BEEP.
12. How would you define XML messaging?
XML messaging is responsible for encoding the information in XML format to make it understandable by every end, like XML-RPC and SOAP.
13. Define the Service Description layer protocol of SOAP?
The service description layer protocol is responsible for describing user Interface to web services such as WSDL.
14. Define the Service Discovery layer?
The service discovery layer provides functionality such as UDDI and centralizes all the services to a universal registry.
15. What XML-RPC Does?
XML-RPC is responsible for doing Remote Procedure Calls by making use of XML messages.
16. Explain JAXR?
XML registries from Java Platform are retrieved using JAXR, which is a standard API.
17. Explain UDDI?
UDDI is the directory that can be used to discover or publish web services that are available publicly. UDDI, in its complete form, is Universal description, discovery, and integration.
18. Explain Disco?
Disco is responsible for uncovering schema documents of various web services and joins multiple services together. Disco is also known as Discovery.
19. Define WSDL?
The WSDL stands for Web Service description language. As the name suggests, WSDL describes web services, and it incorporates-
End Point of Web service, the method used by Web Service and the properties it supports like data type and protocols.
20. How will you provide an API to users?
The simple way to provide an API to the users is to make use of an open table. The open table is XML schema pointing to a web service.
21. How can we obtain a proxy object of Web service at the client-side?
- We would first need to make use of UDDI Node to access a list of web services.
- The services we will obtain from UDDI would contain end-points to DISCO or WSDL documents.
- We can now build a proxy object by parsing DISCO or WSDL document.
22. What do you mean by .Net Web service?
- .Net web service is a component responsible for transmitting information and services to other applications on the network.
- .NET utilizes standard web protocols like HTTP and SOAP to send information and services over the network.
- The .NET framework helps enable people access applications that do not depend on their system OS or Hardware but are browser dependent.
23. Which protocol does Cobra use?
Cobra uses Inter Internet Object Protocol or IIOP. COBRA stands for Common Object Request Broker Architecture; it enables us to communicate between two software written in a different language and running on distinct computers.
24. What protocol does DCom use?
Dcom uses Remote Procedure Calls or RRC protocol.
25. How web services differ from Cobra and Dcom?
Web services exchange information between application over standard web protocols like HTTP and SOAP using XML format.
COBRA exchanges information between applications using protocols like IIOP. COBRA stands for Common Object Request Broker Architecture, and it enables us to communicate between two software written in a different language and running on distinct computers.
Dcom uses a Remote procedure calling protocol to exchange information between application.
Dcom and Cobra use non-standard protocols to receive pr send messages, whereas Web services s standard protocols like HTTP and SOAP.
26. Why do we use .Net web services?
.Net web services are useful for implementing three-tier architecture and provides multiple ways to use middle-tier components through the internet.
.NET utilizes SOAP protocol for transport. Thus, they could easily communicate across firewalls.
27. What data types of web service support?
.NET web services support all the data types that XML Schema supports.
.NET web services use XML standards to transport messages. Web services do not help proprietary like FileSteam, Event log that is .NET specific.
DataTable and DataSet can be used to return information from Database, but ADO.Net objects like Dataraw and DataCollumn can’t be used.
28. What do you mean by Vsdisco Files?
Vsdisco files are the disco files capable of supporting the Dynamic discovery of web services.
These files are placed in a directory on the webserver to get a reference to all ASMX and DISCO files in the host directory.
29. Explain Dynamic Discovery and its working?
Web services dynamic discovery is a discovery protocol, more precisely a multicast discovery protocol that returns dynamically generated disco documents.
30. How could you block a browser from caching an Aspx page?
It is possible to block a browser from caching an Aspx page. To do so, you can call SetNoStore on the HttpCachePolicy object.
When you call SetNoStore on the HttpCachePolicy object, it will return Cache-Control: private and no-store header in the response.
31. Explain Windows service, and how does it differ from EXE?
Windows Services are NT service that runs in the background, but Executable files are not like windows application is not possible to click and run EXE.
32. What web service standards would W3C supports?
World Wide Web Consortium is responsible for standardizing protocols used in Web services. World Wide Web Consortium is pursuing standardization of SOAP.
A web service activity has been announced by World Wide Web Consortium that would look at current SOAP, Web Services Description Working Group, Web Services Architecture Working Group to work for WSDL, and to create a framework for web service protocols.
33. How is SOAP used in .Net web services?
SOAP uses XML format for RPC. RPC is remote procedural calls; SOAP utilizes XML remote procedural calls.
The request and response are packaged in SOAP. A SOAP message incorporates information to process the request as required by web service.
SOAP could transmit different data types like DateTime, XmlNode, their arrays, and user-defined objects.
34. Define the Web method attribute in ASP.NET?
Web method attribute is used to expose the method as part of the XML web service, and this could be achieved by attaching a web method attribute to a public method. This makes the method web-callable. The following components can be used to change your web method:
- Description
- CacheDuration
- MessageName
- BufferResponse
- EnableSession
- TransactionOption
35. Do web services have any disadvantages? If they do have, then list them.
COBRA, RMI, and Dcom have better performance than web service.
The XML standard used is not at par with industry standards for both efficiency and encoding.
A system crash may occur when accidental power-off happens, especially before the client has made a request to the server, and it has not been responded to.
36. What file extension does a web service uses?
The file extension used is XML and JSON.
37. Why should one choose UDDI over Disco?
The reason why one would choose UDDI over Disco is, UDDIU directory has some benefit over the Disco file.
UDDI directory allows us to find several web services by various groups at a single place while this is not the case with Disco.
38. Can you explain the Eventlog class?
To access the Windows event log from windows service, we can use the event log class.
It is also helpful in customizing the record and information stored in the windows event log. You can write, read, or delete Event sources.
39. Is there any way to block unauthorized access to your web service? If yes, then elaborate.
You can prevent unauthorized people from accessing web service by implementing message-based security, encryption, authentication, controls.
To make sure an unauthorized person cannot authorize your web service. You can make use of element.
Authorization element will only let your authorized people access the web service. You can set this according to their role.
40. Which namespace is essential to be imported in your code to build a web service?
The namespace, which is essential to be imported in the code to build a web service, is called System.
41. Is it possible to install a win service developed in .Net in win98?
No, it is possible to install a win service developed in .Net in win98. This is not possible, even if the machine supports the .NET framework.
42. How can you deploy a web service?
To deploy a .Net web service, we would need to copy or upload the.ASMX file and the.DISCO files to the appropriate directories, this would deploy the web service.
43. Why do we use a .disco file?
The .Disco file is responsible for pointing to the WSDL file. The WSDL file, in return, points to the web service. The disco document is in XML format.
44. Explain Virtual Hosting?
The term virtual hosting is used to represent a method to host more than one domain name on a single server.
All the services do not share the same host but still share server resources and processing cycles.
45. Explain Full-service web hosting and Uptime?
A full-service web hosting offers a variety of services like setting up email, webmail, additional users, databases, setting up SSL certificates, XML p3p privacy policies, etc.
Uptime is a quantity that represents the reliability of a server or computer system. It is the percentage of time for which the order of the hardware has been operating without going down. Uptime is the opposite of downtime.
46. Could you explain Domain Parking?
Using a domain without associating it with any website or other service is what we call domain parking. You could park your domain to any hosting by associating a service with it.
47. Describe what cPanel is?
cPanel is a software that allows us to manage a web hosting server. cPanel LLC developed it. It serves as a control panel for hosting services.
48. What do you mean by Webhost manager?
A WebHost Manager is a web application that enables us to get us administrative control of our dedicated server.
It could serve a variety of purposes, like adding domains to the server, Cpanel maintenance, etc.
49. Do you know about the Entrust identification service?
Entrust identification services are derived from the Entrust Security Transaction Platform.
It enables companies and organizations to have control over identities that could perform web service transactions.
50. How SSL and TLS are related to each other?
SSL is the abbreviation for a secure sockets layer, whereas TLS stands for transport layer security.
They both are cryptographic protocols. Both cryptographic protocols are used to authenticate data transfer systems, servers, applications, and users.
51. What secure encryption and authentication mechanisms do Iis 6.0 support?
The secure encryption and authentication mechanisms that iis 6.0 supports are as follows – Basic authentication, Digest authentication, Advanced digest authentication, Certificate-based Web transactions that use PKCS #7/PKCS #10, Fortezza, SSL, Server-Gated Cryptography, Transport Layer Security, etc.
52. Differentiate between primary and dynamic disk?
The primary disk is the same configuration of the hard drive as used with MS-DOS. The central disk used logical drives to manage data and partitions on the drive. It includes primary and extended partitions.
Dynamic disk is yet another hard disk configuration that includes dynamic volumes. The partitions can be extended, and specialized disk volumes could also be created.
53. What Presentation Layer does in the OSI model?
The function of the Presentation layer in the ISI model is to present that to the application layer.
The presentation layer does so in a well-defined and standardized format. The same layer is also known as the syntax layer.
54. List some features of the application pool in Lis?
The features of the application pool in IIS are as follows-
- It isolates applications running even on the same server.
- It could be used to separate different apps requiring security.
55. Define the App pool?
The app pool is similar to the app domain in functionality. The App pool provides isolation to each application at the process level.
The app pool can be used in both ASP.Net and Non-ASP.Net applications.
56. Define the app domain?
The app domain is a concept used in ASP.Net to provide isolation for each application.
A unique app domain is associated with each ASP.Net application.
58. Explain what idempotent means?
All the methods that do not change the state of the resource after initial application; as a result of multiple successful requests are called idempotent.
57. State the difference between posts and put HTTP methods?
The significant difference between post and put HTTP methods is- The job is not idempotent, and it is used to create new resources. Put is idempotent and put useful in updating a resource.
Final Words
These were some questions that are often asked in the web services interview. A career in the field of web services is full of opportunities. The area of web services is growing day by day.
Apart from having a look at these questions and answers, you should also strive to enhance your overall programming knowledge.
I hope these questions would help you perform better in the dialogue with the interviewer and start your professional career in web services.
Thanks for reading and wish you all the luck for your next interview.
