Java Web Services Tutorial

Q. What is a Web Services In Java?

Q. What are the advantages of web services?

Q. What is the Use of Web Services in Java?

Q. How Does a Web Service Work?

Q. Why Web Services?

Q. Why do we Need to Use Web Service?

Q. What is a Web Services In Java?

In simple words, services that can be accessed over a network are called web services. So how does it differ from the web application, they are also services that are accessed over a network. Few attributes clarify this difference.

Web packages are supposed for users and to be accessed in-browser having human-readable format whereas web offerings are intended for packages to get right of entry to records in the format of XML, JSON, and so on.
Web applications continually use HTTP/HTTPS protocol whereas conventional web services use SOAP protocol. Recently REST is getting popularity this is an architecture style and nearly all times run on HTTP/HTTPS protocol.

Web applications are not meant for reusability whereas this is one of the benefits of web services.

The web application can access web services to access some data or to perform some tasks, web services can’t access web applications to fetch some data.
Web applications are capable to hold user session, web offerings are stateless.

I hope the above differences are good enough to clear any confusion with web applications and web services. Both are different concepts and meant for different purposes.

Q. What are the advantages of web services?

Some Of the advantages of web services are:

Exposing Business Functionality on the network – A net provider is a controlled code unit that provides a few kinds of the capability to customer applications or end-users. This functionality may be invoked over the HTTP protocol which means that it can also be invoked over the internet. Web offerings may be used everywhere at the net and offer the essential capability as required.

Interoperability amongst programs – Web services allow various applications to communicate with each different and proportion information and services amongst themselves.

A standardized Protocol that all of us are familiar with – Web offerings use standardized enterprise protocol for the communique. All 4 layers Service Transport, XML Messaging, Service Description, and Service Discovery layers) use properly-defined protocols in the net services protocol stack.

Reduction in cost of communication – Web offerings employ SOAP over HTTP protocol, which helps you to use your present low-cost internet for imposing web offerings.

Now, allow’s move also and recognize the various types of internet services which can be used for a verbal exchange on a day to day foundation.

Types of Web Services
Generally, there are types of internet services as follows:

Soap Web Services
RESTful Web Services
Let’s get into the details of those web services.

1. Soap Web Services
Simple Object Access Protocol (SOAP) is a well-known protocol specification for message exchange based on XML. Communication between the internet service and the customer takes place the usage of XML messages. A simple internet provider structure has two issues: viz. Client and Service company.

Soap internet carrier – Java Web Services
In the above parent, you could observe how the purchaser will speak with the service provider. So to speak, the purchaser must recognize statistics like the Location of web services server, Functions to be had, signature and return varieties of feature and enter-output formats. The provider will create a well-known XML record as a way to have all the above records. So, if this file is given to the purchaser then it will likely be able to get entry to web carrier.

So that’s the way it works. Now allow’s flow further and recognize what’s RESTful web services.

2. RESTful Web Services
Representational State Transfer (REST) is a stateless client-server structure in which the internet services are considered as assets and may be recognized using their URLs. It includes additives REST server which presents get admission to the assets and a REST client that accesses and modify the REST sources. Take a study under the parent for the same.
In this REST architecture fashion, the purchaser and server exchange the representations of the sources via the usage of a standardized interface and protocol. REST is not a selected protocol, however, when people speak approximately REST they normally suggest REST over HTTP. The response from the server is taken into consideration as the representation of the sources. This representation can be generated from one or a greater quantity of sources. RESTful internet services use HTTP protocol strategies for the operations they perform. It consists of techniques like getting, POST, DELETE, and so on.

Now that you know what are SOAP and RESTful internet offerings, let’s pass similarly and see how sincerely it works with the help of an example.

Java Web Services API

There are two essential APIs defined using Java for growing internet carrier programs.

1. JAX-WS: It is particularly for SOAP internet services. There are two approaches to put in writing JAX-WS software code: with the aid of RPC style and Document style.

2. JAX-RS: It is especially for RESTful net services. There is specifically 2 implementation presently in use for growing JAX-RS software: Jersey and RESTeasy.

Q. What is the Use of Web Services in Java?

Interoperability. Web services allow various applications to speak to every different and percentage statistics and services among themselves. Other packages can also use Web offerings. For example, a VB or .NET application can speak to Java internet offerings and vice versa.

A Web service is any piece of software that makes itself available over the internet and makes use of a standardized XML messaging gadget.

XML is used to encode all communications to an internet provider. For example, a client invokes an internet provider through sending an XML message, then waits for a corresponding XML reaction.

As all verbal exchange is in XML, net services aren’t tied to anybody running gadget or programming language—Java can speak with Perl; Windows applications can communicate with Unix packages.

Web services are self-contained, modular, disbursed, dynamic programs that can be described, published, positioned, or invoked over the network to create merchandise, approaches, and deliver chains. These programs can be local, allotted, or internet-primarily based. Web offerings are constructed on the pinnacle of open standards which include TCP/IP, HTTP, Java, HTML, and XML.

Web offerings are XML-based information alternate structures that use the Internet for direct application-to-utility interaction. These structures can consist of applications, gadgets, messages, or documents.

An internet carrier is a group of open protocols and standards used for changing statistics between applications or structures.

Software packages written in numerous programming languages and strolling on diverse structures can use web services to exchange records over pc networks just like the Internet in a way similar to an inter-system communique on a single computer.

This interoperability (e.G., among Java and Python, or Windows and Linux packages) is due to Using open standards.

To summarize, a complete net provider is, therefore, any carrier that −

Is to be had over the Internet or personal (intranet) networks

Uses a standardized XML messaging gadget

Is no longer tied to anybody working machine or programming language

Is self-describing thru a common XML grammar

Is discoverable via an easily locate mechanism

Components of Web Services
The primary internet offerings platform is XML + HTTP. All the same old net services work using the following components −

SOAP (Simple Object Access Protocol)

UDDI (Universal Description, Discovery, and Integration)

WSDL (Web Services Description Language)

All these additives have been mentioned in the Web Services Architecture bankruptcy.

Q. How Does a Web Service Work?

A Web carrier allows verbal exchange among numerous programs using open requirements which include HTML, XML, WSDL, and SOAP. A net service takes the help of −

XML to tag the information

SOAP to switch a message

WSDL to explain the provision of the provider.

You can build a Java-based web carrier on Solaris that is available out of your Visual Basic program that runs on Windows.

You can also use C# to construct new internet services on Windows that may be invoked from your net utility that is based on JavaServer Pages (JSP) and runs on Linux

Q. Why Web Services?

Exposing the Existing Function at the network
Net service is a unit of managed code that can be remotely invoked using HTTP.

That is, it can be activated using HTTP requests.

Web offerings allow you to show the capability of your existing code over the network. Once it’s miles exposed in the community, different programs can use the functionality of your program.


Web services allow diverse applications to speak to every other and share statistics and offerings amongst themselves. Other applications also can use net offerings. For instance, VB or .NET software can communicate with Java internet offerings and vice versa. Web services are used to make the utility platform and generation impartial.

Standardized Protocol

Web offerings use standardized industry trendy protocol for the communique. All the 4 layers (Service Transport, XML Messaging, Service Description, and Service Discovery layers) use properly-defined protocols in the internet services protocol stack. This standardization of protocol stack offers the business many advantages including a huge range of choices, discount inside the fee due to competition, and boom inside the best.

Low-Cost Communication

Web services use SOAP over HTTP protocol, so you can use your current low-value net for imposing internet services.

This solution is much less costly in comparison to proprietary solutions like EDI/B2B. Besides SOAP over HTTP, internet offerings also can be implemented on different reliable transport mechanisms like FTP.

Q. Why do we want to apply Web service?

We Should use net offerings as it comes with various advantages listed Below:


Once we broaden a few enterprise good judgment, we can make it reuse for different programs


If 10 special packages require to use our common sense

We can disclose our common sense over a network as a web carrier

So all of the 10 one of a kind utility can access it from the network.


It gives freedom for developers to choose regardless of the generation they want to use for development.

Web services use fixed requirements and protocols and permit us to obtain interoperability.

Hence programs developed in Java, Mainframe, Ruby or every other era can name the web provider and use it.

Loosely coupled

Web service exists impartial of the other elements of the utility that makes use of it.

So any changes to the application may be made without affecting the web carrier.


It could be very easy to install internet software as they’re deployed over general Internet technologies.

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