Web Services Interview Questions and Answers
Web services are modular, self-contained, dynamic and distributed applications that can be published, described, invoked or located over the network to create processes, products and supply chains. These applications can be distributed web-based or local. All of the web services are developed on top of open standards such as HTTP, Java, HTML, TCP/IP, and XML. We will discuss a set of expert picked Restful Web Services Interview Questions with the most suitable answers further here. It is utilized for the machine to machine communication, specifically for transferring machine-readable files such as JSON and XML. Web services are used to communicate one programming language with another, so it’s a medium to achieve interoperability. Due to the high demand for web services, businesses from every niche globally are hiring web service professionals to support them optimally.
Advantages of Restful Web Services
- Web services can expose the existing code functionality over the network so that other applications can use the similar feature of the program.
- Can be used to make the application technology and platform-independent.
- Web services allow various applications to communicate with each other and share services and data among themselves.
- The use of standardization protocol in web services benefits businesses with a wide range of choices, cost reduction, and increased quality.
- Web services utilize SOAP over HTTP protocol, so developers can work with existing low-cost internet for implementing web services.
Now, let’s discuss the most asked Restful Web Services Interview Questions for your acknowledgment, so you can ensure future success with your interviews.
Most Frequently Asked Web Services Interview questions
Here in this article, we will be listing frequently asked Web Services Interview questions and Answers with the belief that they will be helpful for you to gain higher marks. Also, to let you know that this article has been written under the guidance of industry professionals and covered all the current competencies.
Web service is a standardized way to integrate web-based applications using SOAP, XML, UDDI and WSDL open standards over an internet protocol backbone. After this, developers can add web services to GUI to offer specific functionality to users.
Here are the advantages of web services:
- Integration and interconnectivity with the legacy systems
- Reduced operational costs
- Faster system development
- Better interfaces with clients
There are two types of web services:
- SOAP web services: SOAP or Simple Object Access Protocol is based on transferring XML data as SOAP messages.
- RESTful web services: Used to build web services that are maintainable, lightweight and scalable in nature.
Simple Object Access Protocol or SOAP is a messaging protocol which allows programs running on disparate operating systems to communicate using HTTP (Hypertext Transfer Protocol), and it's XML (Extensible Markup Language).
Advantages:
- Simple to use
- Platform and language independent
- Firewall friendliness
- Use of open standards
- Universal interoperability
- Extremely versatile
- Highly flexible
- helps to create payload format and extensible protocol
Disadvantages:
- Extreme reliance on HTTP
- Statelessness
- Considerably slow
- Serialization by value and not by reference
WSDL or Web Services Description Language is an XML format for describing network services as a set of endpoints operating on messages containing procedure-oriented or document-oriented information. It allows developers to exchange info over a particular protocol between applications.
Continue further to access best web services interview questions for experienced as well as freshers.
Web services require the following security:
- Username/Password approach
- X.509 approach: It identifies the user by a public key infrastructure
- Kerberos
- Digital Signature: XML signature to be used to protect data
- Encryption: XML encryption to be used to protect data
Universal Description, Discovery, and Integration or also known as UDDI is an XML based standard used for describing, finding and publishing web services. It’s a specification for a distributed registry of web services and uses Web Service Definition Language (WSDL) to define interfaces of web services.
REpresentational State Transfer or REST web service is an architectural style for developing. It’s favorite due to its simplicity and fact that it builds upon existing features and systems of HTTP in order to achieve its objectives, as opposed to creating entirely new frameworks, technologies, and standards.
| S.no | SOAP | REST |
|---|---|---|
| 1. | It stands for Simple Object Access Protocol | It stands for Representational State |
| 2. | It was a protocol and designed with a specification. | It’s an Architectural style in which web services can be treated as a RESTful service. |
| 3. | Can’t make use of REST | Can make use of SOAP |
| 4. | It uses service interfaces to expose its functionality to applications | It uses Uniform Service locators to access to the components on the hardware device |
| S.no | JAX RPC | JAX WS |
|---|---|---|
| 1. | Services based on JAX RPC uses the RPC programming model to invoke operations of a web service. RPC programming model invokes stubs located on the client to call methods on a remote server. | Services based on JAX WS uses annotations to declare the endpoints of web service. The annotations use the requirement of deployment descriptors |
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The sun-jaxws.xml file is present in SOAP web services and helps in offering the endpoints details when JAX WS web services get deployed in a servlet container. Placed in WEB-INF directory, the sun-jaxws.xml file contains implementation class, endpoint name, meta information, and a URL pattern.
BEEP or Blocks Extensible Exchange Protocol is connection oriented internet protocol. SOAP messages inherit the additional service qualities from BEEP to maintain session context at the receiver and the sender.
SOA or Service-Oriented Architecture is a collection of services. These services present in SOA communicate with each other and involve simple data passing or involve coordinating two or more services to perform an activity.
Public Key Infrastructure or PKI is a framework of cybersecurity and encryption that protects communications between the server and users.
It works with two different cryptographic keys; a public key and a private key.
| S.no | SOA | Web Service |
|---|---|---|
| 1. | SOA or Service Oriented Architecture is an architectural concept focused on having different services communicating with each other to carry out a more significant function. | A web service is a fundamental building block present in a Service Oriented Architecture. When multiple functions get combined, an application is created under an SOA |
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In web service, JAXP is used to process XML data using applications written in the JAVA programming language. It works with a pluggability layer that allows you to plug in an implementation of the DOM or SAX APIs.
An XML signature is used to sign in recourse outside its containing document of XML. It’s also called the enveloped signature.