Clients can access a Java EE application as a remote web service in addition to accessing it through HTTP, RMI/IIOP, and JMS. Web services are implemented using the Java API for XML-based RPC (JAX-RPC). A Java EE application can also act as a client to web services, which would be typical in network applications.
Web Services Description Language (WSDL) is an XML format that describes web service interfaces. Web service consumers can dynamically parse a WSDL document to determine the operations a web service provides and how to execute them. The Application Server distributes web services interface descriptions using a registry that other applications can access through the Java API for XML Registries (JAXR).