SOAP and REST: Distinguishing Java-based Web Services

Establishing communication between the application and a platform—that’s a basic principle of web services. And there are hundreds of thousands of applications built in different languages to run on varied platforms. For instance, Java-based applications functioning on Linux platforms can easily interact with PHP-based applications that are functional on Windows. These web services are bifurcated into two, namely: SOAP and REST.

SOAP is an acronym for Simple Object Access Protocol and REST for Representational State Transfer. SOAP was originally developed by Microsoft as a web-access protocol backed by standards that must be followed meticulously. While on the other hand, REST is an architectural type that doesn’t follow much of the standards like SOAP, as it can be run naturally.

Before we actually distinguish these two web services, let us first explore each of them in detail.

Exploring SOAP

SOAP specifically functions on XML and it provides exclusive messaging services. It was originally developed by Microsoft to facilitate the smooth functioning of other web technologies like Distributed Component Object Model (DCOM) and Common Object Request Broker Architecture (CORBA). One reason why this technology never really took off is because they rely on the binary system for messaging, which is not only primitive but also less functional than XML on the internet.

Soon after the initial release, Microsoft submitted SOAP to the Internet Engineering Task Force (IETF) where standards were integrated to it for further processing. Apart from its key acronym, you would find SOAP being associated with other abbreviations like WS-Addressing, WS-Policy, WS-Security, WS-Federation, WS-ReliableMessaging, WS-Coordination, WS-AtomicTransaction, and WS-RemotePortlets. This clearly exhibits how popular and extensible SOAP is.

Many times, XML code used to send requests and get responses become complicated. Also, there are instances when you need to create requests manually. As referred by WSDL (Web Services Description Language), the complexity of working with SOAP largely depends on the language you are using.

One reason why many people still find SOAP useful is its error-handling capability. Along with an option to manually fix the bug, you can also utilize the automated error-handling option.

Exploring REST

Users who found SOAP a bit complex and tedious to use relied on REST as a web service. REST is lightweight and an architectural-type web service that assists in designing networked applications. Also, it doesn’t use XML files, instead, it uses simple URL requests along with four varied HTTP 1.1 verbs namely GET, POST, PUT, and DELETE in order to perform tasks.

Primarily, you can see output results of REST-based services in Command Separated Value (CSV), JavaScript Object Notation (JSON), and Really Simple Syndication (RSS). This means you can easily get the output in the desired form that can be conveniently parsed into other languages.

The core function of REST includes:

• Sending requests and receiving responses
• Involves both clients and servers during the process
• All the requests and responses are made around the request representation of resources.

REST recognizes every resource (e.g. User, Lottery, etc.) and each resource implements a standard uniform interface (typically HTTP interface). These resources have names and addresses (URIs), and each resource has one or more representation (like JSON or XML). Resource representations move across the network usually over HTTP.

RESTful web APIs (or RESTful web service) is another popular term that includes web API integrated with the help of HTTP and REST principles. These APIs efficiently leverage the portability of user interface on platforms.

SOAP or REST?

Prior to choosing one of the two, make sure you know all the basic parameters that connect and distinguish these web services from the other. Picking the right web service depends on the extent to which the web service meets your requisites. So choosing either REST or SOAP wholly depends on your work requisites.

Why SOAP?

The major advantage of using SOAP is that you can easily introduce usable client proxy from the service description to generate calls and required data types. This WSDL updated version 2.0 supports varied HTTP markups while WADL (Web Application Description Language) doesn’t provide much support in this context.

Here are some other reasons why you might want to consider using SOAP:

• Reliable and Realistic Messaging: REST doesn’t hold any standard messaging system that offers no automation system to request or receive information. Whereas SOAP consists of an inbuilt messaging system that helps in creating an end-to-end messaging system for clients.
• Security: Don’t be surprised to know if SOAP is compatible to the SSL and supports WS-Security that helps in adding more enterprise security features. Along with point-to-point system for identities, SOAP supports the implementation of data privacy and integrity in the system. Integrated with advanced enterprise functions don’t just make it secure but give an added security functionality.
• Auto-Transaction: Completing ACID transactions on any service using SOAP can be a wise decision. REST supports transaction but it is not compliant to ACID.

Why REST?

As REST involves standard HTTPs that are much easier to work on, (also creating APIs, documentation, etc.) clients get easier with on REST. Moreover, you can use different data formats while working with REST as compared to SOAP that only allows XML formats. JSON works best for data and parses in a short span of time. This helps in providing better support for browser clients.

Undoubtedly, the performance and scalability of REST are better than of SOAP. Also, RESTful reads can be easily cached. A few years back, Google used to provide only SOAP for all its services but soon realizing the dynamism of REST, it started favoring REST since 2006. And unsurprisingly, REST influences most part of their web service architecture.

Now that you have an idea about how the two are different from one another and function in different realms, let us now summarize these popular web services below.

SOAP  REST 1 SOAP = Simple Object Access Protocol REST = Representational State Transfer 2 It is a protocol that shows how client and server communicate with each other It is an architectural style based on which are RESTFul web services 3 SOAP web services have JAX-WS specification RESTful web services have JAX-RS specification 4 Supports only XML data format Supports different data formats like plain text, HTML, XML, JSON etc. 5 Slow parsing of XML markup delays the request-processing Quick processing of RESTful markup as it includes JSON that is easier to parse 6 Do not use web-caching mechanism Full-fledged utilization of caching mechanism 7 Unable to use REST architecture SOAP based web services can also be used in RESTful style 8 Heavy-weight and require XML parsing along with specific header for every request/response As compared to SOAP, it is light-weight and requires no parsing 9 Comes with definite standards that are a must to establish a smooth communication Not many standards are defined, thus facilitating implementer to execute things in its own way 10 Needs more resource and bandwidth due to heavy payload created in XML file REST uses JSON hence, it requires less resource and bandwidth. Also, the payload built in JSON is not that same as XML 11 Uses WS-security extensions to ensure security. Using secured HTTP SSL and WS-Security encryption for securing calls and messages simultaneously Comprises of inbuilt security measures. Only HTTP SSL encryption is used to secure calls in REST 12 Utilizes WSDL (Web Services Description Language) to describe the functionality of a web service Utilizes WADL (Web Application Description Language) to describe the functionality of a web service 13 Consists of an inbuilt error handling feature. So whenever a wrong request is sent, SOAP response will show an error message No specific inbuilt error handling feature. So developers need to check and regulate the response codes on their own 14 Uses XML for exchanging information. This is why XML parsing is complex and is advised to be done under expert supervision Uses JSON for sharing information. JSON comes with an inbuilt support for JavaScript that makes parsing quicker and easier. 15 With standard conventions, SOAP offers pre-existing compatibility for WS extensions. Also, due to its security functions, SOAP is mostly preferred for enterprise applications As REST doesn’t use any standards, it is getting popular among developers and web users across the globe 16 SOAP requires a lot of knowledge and expertise to work on it. This ultimately is a time-consuming process The learning curve of REST is less which means you can easily work on it and can easily use it to send and utilize information 17 SOAP messages are not just HTTP specific. They can be easily sent over different protocol as SOAP works independently of language and platform REST specifically requires HTTP to function

Wrapping Up!

Well, if you have a myriad of resources and security seems to be a major concern for you, then without any hesitation go for SOAP web services. Especially if you have banking-related work concerns, SOAP could be the best choice as it provides the needed security.

While on the other hand, if security isn’t an issue for you and you are provided with limited resources, you may be better off to pick RESTful web service. Also, if you want to create APIs that can be easily used by other developers, simply go for REST.

Other tutorials you might find interesting:

• REST API Tutorial: How to Design a Sustainable Web API
• Intro to SwingWorker in Java
• Fetching Data from an API

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Author’s Bio

David Meyer is an expert web developer employed at CSSChopper for the last 8 years. He also enjoys writing well-researched articles about the latest trends in the web industry.