Oracle OSB-SOA-BPEL Interview Question and Answer – Part 6

In this article, we will discuss interview question with their justification on Oracle OSB, SOA and BPEL

This is part-6 of Oracle OSB-SOA-BPEL interview question series

Q) Explain SOA architecture ?

  • Service-Oriented Architecture (SOA) is a set of principles and methodologies for designing and developing software in the form of interoperable services
  • These services are well-defined business functionalities that are built as software components (discrete pieces of code and/or data structures) that can be reused for different purposes
  • SOA design principles are used during the phases of systems development and integration
  • SOA generally provides a way for consumers of services, such as web-based applications, to be aware of available SOA-based services

Q) What is the use of SOA in IT industry and how it resolves the problem ?

  • Remove redundancy
  • Reuse
  • accelerated delivery
  • well defined services that interact with each other

Q) What is SCA ?

  • Service-component architecture (SCA) is a group of specifications intended for the development of applications based on service-oriented architecture (SOA), which defines how computing entities interact to perform work for each other
  • SCA provides a model for composing applications that follow Service-Oriented Architecture –> Which is designed and deployed as a single unit
  • In Oracle SOA 11g, SCA composite contains 4 main components namely,
    • Mediator – message routing and transformation & filtering capabilities
    • BPEL – for service orchestration to manage complex interaction patterns
    • Human Task – for human workflow capabilities
    • Business Rules – that executed external to process context and its outcome influence the process flow

Q) What is Web service ?

  • Web services are application components, which are self-contained and self-describing and provide services based on the open protocol communication (i.e. SOAP UI, HTTP over the Internet)

Web Services:

  • Web services are application components
  • Web services communicate using open protocols
  • Web services are self-contained and self-describing
  • Web services can be discovered using UDDI
  • Web services can be used by other applications
  • XML is the basis for Web services

 Q) What are services in SOA ?

  • Services are business functionality that forms the foundation for building application by using an SOA approach
  • SOA application can be thought of functionality that aggregates the related services, by reusing other available services to complete the automation of a business process
  • Service functionality must be described using standard interface and message structures to make them highly accessible and reusable
  • The most widely used WS standards are XML, XSD, WSDL and message transportation through HTTP
  • Services created in SOA can be stored in Enterprise Registry for design time or SOA Governance process & can be accessed via Service Registry

Q) What are Service Data Objects (SDO) ?

  • Service Data Objects is a technology that allows heterogeneous data to be accessed in a uniform way
  • A SDO exposes any data source as a service, which enables retrieval & manipulation of the data in an XML format through web service

Q) What are Enterprise Registry and Service Registry ?

  • To extend the idea of service life cycle management ideally an ER & SR such as OER & OSR should be considered for managing services in an enterprise across development and production run time environment
  • An ER & SR enables service descriptions and artifacts to be centrally located, stored and versioned and can be monitored according to SOA Governance
  • Services created in SOA can be stored in Enterprise Registry for design time or SOA Governance process & can be accessed via Service Registry
  • A Service Registry enables application to look up services using a service key for location independence

Q) What are the main functions of OSB, Mediator & BPEL ?

OSB:

  • The larger, powerful service bus
  • Extended functionality important for enterprise-wide integration like Message Throttling, Service Pooling and Reliable Messaging
  • Development through Eclipse IDE or Web Console
  • Message Transformation over XQuery & XSLT
  • OSB specific deployment

Mediator:

  • The tiny, light weight service bus
  • Stateless Messaging
  • Value Mapping and Cross-Reference Tables for supporting Canonical data models
  • Implementation of VETRO Pattern (Validate-Enrich-Transform-Route-Operate)
  • Development through JDeveloper IDE
  • Message Transform with XSLT
  • Can be used and deployed as a SCA Component
  • Event Delivery Network for Publish-Subscribe semantic

BPEL:

  • Primarily for Stateful and long running processes
  • Orchestrating Service Calls
  • Implementation of Composite Services
  • Integration of Rules Engine and Human Workflow
  • Instance Monitoring

Q) What are the various BPEL activities in SOA 11g ?

  • Web Service: invoke, partner link, Receive, reply
  • Standard Activities: assign, compensate, empty, terminate, throw, and wait
  • Structured Activities: flow, pick, scope, sequence, and switch, while

 

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