Interview Questions
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1.What are web services?

Web services are open standard XML, SOAP, HTTPetc. based Web applications that interact with other web applications for the purpose of exchanging data. Web Services can convert your existing applications into Web-applications.

2.What are the features of web services?

Following are the features of Web service −

  • It is available over the Internet or private intranet networks.
  • It uses a standardized XML messaging system.
  • It is not tied to any one operating system or programming language.
  • It is self-describing via a common XML grammar.
  • It is discoverable via a simple find mechanism.

3.What the components of a Web Service?

The basic web services platform is XML + HTTP. All the standard web services work using the
following components −

  • SOAP SimpleObjectAccessProtocol
  • UDDI UniversalDescription, DiscoveryandIntegration
  • WSDL WebServicesDescriptionLanguage

4.How Does a Web Service Work?

A web service enables communication among various applications by using open standards such as HTML, XML, WSDL, and SOAP.
You can build a Java-based web service on Solaris that is accessible from your Visual Basic program that runs on Windows.
You can also use C# to build new web services on Windows that can be invoked from your web application that is based on JavaServer Pages JSP and runs on Linux.

5.What is the purpose of XML in a web service?

A web services takes the help of XML to tag the data, format the data.

6.What is the purpose pf SOAP in a web service?

A web service takes the help of SOAP to transfer a message.

7.What is the purpose of WSDL in a web service?

A web service takes the help of WSDL to describe the availability of service.

8.What are the benefits of Web Services?

Following are the benefits of using web services −

  • Exposing the Existing Function on the network − Web services allows you to expose the functionality of your existing code over the network. Once it is exposed on the network, other application can use the functionality of your program.
  • Interoperability − Web services allow various applications to talk to each other and share data and services among themselves.
  • Standardized Protocol − Web services use standardized industry standard protocol for the communication. All the four layers
  • ServiceTransport, XMLMessaging, ServiceDescription, andServiceDiscoverylayers use well-defined protocols in the web services protocol stack.
  • Low Cost of Communication − Web services use SOAP over HTTP protocol, so you can use your existing low-cost internet for implementing web services.

9.What do you mean by Interoperability of Web Services?

Web services allow various applications to talk to each other and share data and services among themselves. Other applications can also use the web services. For example, a VB or .NET application can talk to Java web services and vice versa. Web services are used to make the application platform and technology independent.

10.What do you mean by loosely coupled architecture of Web services?

A consumer of a web service is not tied to that web service directly. The web service interface can change over time without compromising the client's ability to interact with the service. A tightly coupled system implies that the client and server logic are closely tied to one another, implying that if one interface changes, the other must be updated. Adopting a loosely coupled architecture tends to make software systems more manageable and allows simpler integration between different systems.

11.Do Web services supports Remote Procedure CallsRPCs?

Web services allow clients to invoke procedures, functions, and methods on remote objects using an XML-based protocol. Remote procedures expose input and output parameters that a web service must support.
Component development through Enterprise JavaBeans EJBs and .NET Components has increasingly become a part of architectures and enterprise deployments over the past couple of years. Both technologies are distributed and accessible through a variety of RPC mechanisms.
A web service supports RPC by providing services of its own, equivalent to those of a traditional component, or by translating incoming invocations into an invocation of an EJB or a .NET component.

12.What are the behavioral characteristics of web services?

Web services have the following special behavioral characteristics −

  • XML-Based − Web Services uses XML at data representation and data transportation layers.
  • Loosely Coupled − A consumer of a web service is not tied to that web service directly.
  • Coarse-Grained − Businesses and the interfaces that they expose should be coarsegrained. Web services technology provides a natural way of defining coarse-grained services that access the right amount of business logic.
  • Ability to be Synchronous or Asynchronous − Asynchronous clients retrieve their result at a later point in time, while synchronous clients receive their result when the service has completed. Asynchronous capability is a key factor in enabling loosely coupled systems.
  • Supports Remote Procedure CallsRPCs − A web service supports RPC by providing services of its own, equivalent to those of a traditional component, or by translating incoming invocations into an invocation of an EJB or a .NET component.
  • Supports Document Exchange −Web services support the transparent exchange of
  • documents to facilitate business integration.

13.What are the benefits of having XML based WEB services?

Using XML eliminates any networking, operating system, or platform binding. So Web Services based applications are highly interoperable application at their core level.

14.What is the benefit of a Web services being loosely coupled?

The web service interface can change over time without compromising the client's ability to interact with the service. A tightly coupled system implies that the client and server logic are closely tied to one another, implying that if one interface changes, the other must be updated. Adopting a loosely coupled architecture tends to make software systems more manageable and allows simpler integration between different systems.

15.What is Synchronicity?

Synchronicity refers to the binding of the client to the execution of the service. In synchronous invocations, the client blocks and waits for the service to complete its operation before continuing. Asynchronous operations allow a client to invoke a service and then execute other functions.

16.What are the core Roles in Web Service architecture?

There are three major roles within the web service architecture −

  • Service Provider
  • Service Requestor
  • Service Registry

17.What is the purpose of Service Provider in Web Service architecture?

This is the provider of the web service. The service provider implements the service and makes it available on the Internet.

18.What is the purpose of Service Requestor in Web Service architecture?

This is any consumer of the web service. The requestor utilizes an existing web service by opening a network connection and sending an XML request.

19.What is the purpose of Service Registry in Web Service architecture?

This is a logically centralized directory of services. The registry provides a central place where developers can publish new services or find existing ones. It therefore serves as a centralized clearing house for companies and their services.

20.What are the core layers in Web Service Protocol Stack?

The Web Service Protocol Stack is still evolving, but currently has four main layers −

  • Service Transport
  • XML Messaging
  • Service Description
  • Service Discovery

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