Service Oriented Architecture (SOA) is a current IT architecture and business style of choice. A web service is a preferred style of SOA implementation. Web services interoperability between vendor technologies, especially between IBM WebSphere® J2EE and Microsoft™ .NET platforms, has become an important business requirement for many companies.
The web services provided by SharePoint do provide a vast array of features. The web service interfaces make it very easy to integrate SharePoint capabilities right into your application.
SOA is an architectural style for building software applications that use services available in a network such as the web. It promotes loose coupling between software components so that they can be reused. Applications in SOA are built based on services. A service is an implementation of a well-defined business functionality, and such services can then be consumed by clients in different applications or business processes.
SOA allows for the reuse of existing assets where new services can be created from an existing IT infrastructure of systems. In other words, it enables businesses to leverage existing investments by allowing them to reuse existing applications, and promises interoperability between heterogeneous applications and technologies. SOA provides a level of flexibility that wasn't possible before in the sense that:
Web services are software systems designed to support interoperable machine-to-machine interaction over a network. This interoperability is gained through a set of XML-based open standards, such as WSDL, SOAP, and UDDI. These standards provide a common approach for defining, publishing, and using web services.
Interoperability is the most important principle of SOA. This can be realized through the use of web services, as one of the key benefits of web services is interoperability, which allows different distributed web services to run on a variety of software platforms and hardware architectures.
So we can integrate any SOA based application with SharePoint.