Register Login

Top Best Web Services Interview Questions

Updated Aug 06, 2019

What is web services?

A web service is a software that uses a standardized XML and messaging system and is available on the internet. XML encodes the communications to a web service and are not limited to a single operating system or programming language.

How do web services work?

Web services allow communication between diverse applications in different programming languages by combining open protocols and standards. It mainly uses XML to tag data, SOAP to transmit messages and WSDL to describe service availability.

What are the features of web services?

The features of web services are-

  • Interoperability
  • Institutionalized Protocol
  • A negligible effort of Communication
  • XML-Based for at data representation and data transportation
  • Inexactly Coupled to allow the interface to change without affecting the user's ability to use the service
  • Coarse-Grained
  • Capacity to be Synchronous or Asynchronous

What is the use of web services?

The uses of web services are-

  • Uncover the functionality of code over the network so that other applications may use its functionality.
  • Web services permit several applications to interact and share data as well as services with each other.
  • They use standardized and well-defined industry protocol that allows businesses several advantages like cost reduction due to competition, and quality enhancement etc.
  • It uses SOAP over HTTP protocol, which permits the use of an existing low-cost internet to implementing.

What is the architecture of web service?

The architecture of web services the functionality of the entire framework. It has three distinct levels of function.

  • The provider generates web services and makes it available to the users.
  • The requestor is the client application that contacts the web service. It may be a .Net, Java, or any other programming language based application that searches for functionality through web services.
  • The broker is the application that allows access to the UDDI, which ensures that the client application can trace the web service.

Mention various components/standards of web services?

The various components of web services are-

  • SOAP (Simple Object Access Protocol)
  • UDDI (Universal Description, Discovery and Integration)
  • WSDL (Web Services Description Language)

What are restful web services?

RESTful Web Services use REST Architecture based Web Services that turns all objects into resources to create lightweight and highly scalable services. They are easy to maintain and useful in creating an application program interface for web-based applications.

Which protocol is used by restful web services?

To communicate between client and server, RESTful web services use HTTP protocols.

How to secure restful web services?

The steps to secure RESTful web services are-

  • Give definition to <security-constraint> for every set of RESTful resource.
  • Use <login-config> element for authentication.
  • Give definition to security roles with <security-role> tag and add them to security constraints.
  • Facilitate encryption, with <user-data-constraint> element and ensure that the <transport-guarantee> sub-element is set to confidential.

How to test web services?

The steps to test web services are-

  • Understanding the definition of the WSDL file.
  • Understand the operations of the web service providers.
  • Decide the format of the XML request message.
  • Send XML message request and validate the response with appropriate tool or code.

What are soap web services?

SOAP or Simple Object Access Protocol web services comprise of an XML-based protocol that enables users to access web services over HTTP. The specification of SOAP is relevant across all applications. It defines the communication between web services and client applications.

What are WSDL web services?

WSDL or Web Services Description Language web services are based on XML files that inform a client application of the functionalities of a web service. It allows provides the client with all the information mandatory to establish a connection to a web service and use it.

What is UDDI in web services?

UDDI or Universal Description, Discovery, and Integration is an XML-based platform-independent framework that is useful in describing, publishing, and searching for web services. They describe the interfaces to web services and allows businesses to discover and interact with each other over the Internet.

What is XML web services?

XML Web Services refer to a method of distributing application functionality so that applications can make calls to the centralized functionality with internet protocols like HTTP and SOAP. They themselves return data to the application as XML documents.

Why is XML used in web services?

XML is used in web services as it allows easy transfer of self-descriptive data between applications. It also helps to shift the focus of the developers from the syntax of data to its semantics.

What is the difference between an SOA and a web service?

The differences between an SOA and a web service are-


Web Services

The architecture follows composite applications and data services.

The architecture consists of coarsely-grained, loosely coupled services.

It uses a governance plan for management.

It uses the dynamic discovery of services for management.

SOA follows protocols like SOAP, WSDL, FTP, AJAX, SMTP, CICS, UDDI etc.

Web Services follows protocols like SOAP, WSDL, and UDDI.

The message format is mostly XML but supports other formats as well.

The message format is mostly XML in SOAP.

It is a methodology and not a standard.

It follows W3C and OASIS formats.

What is payload in Web Services?

Payloads in web services pass and return data structures that are too huge for handling as parameters. Commonly, the output payload is the data returned from test results and input payload is the definition of the filter used in the request of test results resource. The predefined structure of the payloads enables simpler creation, consumption, manipulation, and presentation by the client tools.

What is interoperability in Web Services?

Web service interoperability refers to a continuous and automatic connection between software applications so that they may discover and call methods in a software application irrespective of location or platform. The data is in the form of XML request and response documents that can be relocated easily between software packages with the help of HTTP or message-based protocols.

Explain the Web Service Protocol Stack and its layers?

The technology used to implement web service that is organised in layers and stacks. It defines the standard protocol for every layer of a technology in which each layer is dependent on the layers below it. The bottom of the stack has the Transport layer that gives definition to the standards of communication and allows information movement across a network.

It is usually HTTP or HTTPS. The Packaging layer, just above it, defines the standard for the movement of information across a network. It mostly uses the SOAP format. Above it is the Description layer, which classifies the standards of the layers below it and gives definition to the available interface for client use. It mostly uses a WSDL file.

What is Beep in web services?

Blocks Extensible Exchange Protocol or BEEP in web services refer to defining a connection-oriented Internet protocol to inherit the features of service from BEEP. This is useful to maintain session context, both at the sender and the receiver.

What Are The Data Types Supported By Web Services?

The data types supported by web services are:

  • User-defined data type
  • Built-in data type