What are web services?
A web service is a business function that is self-contained and operates over the internet. The W3C defined web service as "a software system designed to support interoperable machine-to-machine interaction over a network". XML is the base for the web services. They communicate using open protocols.Web services are more frequently like Web APIs. These services accessibility can be from internet. A remote system can host these services for different web services. A web service can convert a stand alone / desktop application into a web based / web application. A web services are published or found and utilized through the internet. The web services works on the XML + HTTP platform.
Explain each web service technologies - SOAP, WSDL, UDDI, eBXML and JAX pack.
SOAP: Simple Object Access Protocol is a protocol that is used to exchange structured information at the time of implementing a web service. SOAP is relied on XML. Message format of SOAP usually relies on another protocol of different application layers. Among these the most notable application layer is Remote Procedure Call and HTTP. SOAP forms the foundation layer for web services protocol stack. This stack provides the basic framework for messaging on which the web services are built.WSDL: Web Service Definition Language is used to describe a web service based on XML. WSDL is used for describing Web Services and to locate the services. WSDL consists of the information on what the service is all about, its residing location and the way of invocation the service.
UDDI Universal Discovery Description Integration: To publish and discover the information about web services, UDDI is a specification. It is an XML based standard. This standard is used for describing, publishing, and finding services. These services are found in a distributed environment through the use of a server called registry server.
Electronic Business using XML: EBXML is one from XML family that is based on the standards of OASIS and UN/CEFACT. The mission of this standard is to provide an open xml-based infrastructure which could enable the global use of e-business in an interoperable, secure and consistent manner by all of the partners of trading. This is a unique architecture with unique concepts that are part theory and part implemented within the existing EBXML standards.
JAX PACK: A java API for xml pack that integrates all of the programming interfaces by SUN for different web services development. All these interfaces are made as a single download. JAX PACK is a bundle of JAXB,JAXM,JAX-RPC,and JAXR. Jax pack includes the documentations for support for the SAX,DOM.SOAP,WSDL,XSLT,EBXML,UDDI standards.
Explain the technologies included within JAX pack, i.e. JAXP, JAXB, JAXM, JAX-RPC, JAXR.
JAXP: Java API for xml processing. It provides the validation capability and parsing XML documents. There are three basic parsing interfaces in JAXP are DOM, SAX and Straming API for XML STAX.JAXB: Java Architecture for XML Binding: The java classes are mapped to XML representations. The two main features of JAXB are the ability to marshal Java objects into XML and unmarshal XML back to Java objects.
The Java API for XML Messaging (JAXM) enables distributed software applications to communicate using XML (and SOAP). JAXM supports both asynchronous and synchronous messaging.
JAX-RPC: Java API for XML based RPC. Allows a java based web service that is to be invoked by a Java application provided the description, still being consistent with WSDL description. This can resemble as Java RMI over web services.
Allowing a web service to be implemented at server side as a servlet/jsp or EJB container is the advantage of JAX-RPC.
Explain the web services architecture.
The operations between different software applications, which are running on a variety of platforms and frameworks are supported by a standard called Web services. The web services architecture provides the concepts, model and understanding web services and relationships among the components.The WSA specifies the minimal characteristics that are very common for all web services and a number of characteristics to the needed web services. WSA is called interoperability architecture that means the global elements of a global web service network are identified by this architecture in order to perform the interoperability between the web services.
What are smart web services?
A smart web service understands the situational context and capable of sharing the context with other services. The result of this web service is based on the needs like who, what, when, where it was called.The customer's identity, role of a customer, security policies, physical location of a customer, type of client device are some of the number of the situational circumstances of that a smart web service is aware of.
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