Java Web Services Tutorial

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.