To reuse and integrate applications, one can create web services using XML and HTTP. Web Service Description Language (WSDL) is an XML-based language for describing web services. The web services can be located and invoked over the Web using WSDL from the service providers.
A WSDL contains an element named <binding> which describes how the message is transmitted on the wire and a <service> element that contains the location of the web service.
The <portType> element in WSDL provides a set of operations for the calling clients. Port type is very similar to the concept of interfaces in Java. Java interface specifies methods that a calling client can consume but only by specifying a method of its own. Similarly, Port type in WSDL specifies the operations available that a calling client can consume but only by specifying an operation of its own.
Usually BPEL process consists of multiple steps that provide an overall process. Each step is...