Oracle OSB-SOA-BPEL Interview Question and Answer – Part 1

January 16, 2017 SJ Interview Questions 0

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

This is part-1 of Oracle OSB-SOA-BPEL interview question series

Q) What is Oracle Service Bus or OSB ?

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

Q) What are the key features of Oracle Service Bus or OSB ?

  • Supports Multiprotocol Messaging
  • Enables Location Transparency
  • Handles Dynamic Routing
  • Enables Message Transformation
  • Enables Service Orchestration
  • Supports Message Enrichment
  • Provides Service Security
  • Implements Service Level Agreement

Q) Explain in detail about key features of Oracle Service Bus or OSB ?

  • Dynamically transform and route services using simple and/or complex routing rules and/or message payloads
  • Ability to orchestrate services from existing IT systems with disparate messaging protocols without needing to change the systems and styles
  • Isolate service location changes
  • Rapidly respond to business needs by quickly configuring routing rules based on changes to business rules or existing IT systems, without coding
  • Orchestrate several services to create new one
  • Supports message enrichment
  • Enables optimized, pluggable, policy-driven transport and message level security
  • Implements rules-driven, configurable Service Level Agreement (SLA)

Q) Where does the Service Bus fit in the SOA landscape ?

Significance of OSB in an SOA Landscape :

  • Oracle Service Bus is at the heart of Oracle’s comprehensive business integration solution and belongs to the Oracle Messaging product line
  • Oracle Service Bus is primarily targeted for managing different types of services, and providing traditional message brokering across heterogeneous IT environments
  • The lightweight, stateless, high-performance architecture of Oracle Service Bus and its converged intelligent message mediation and service life cycle management capabilities, make it an ideal core component of distributed services networks
  • It is designed to fit into the broader IT Service-Oriented Architecture (SOA) landscape as a distributed service management intermediary and can be integrated with other Oracle business process management solutions in distributed heterogeneous deployments

Q) How does a Service Bus facilitate a loosely coupled architecture ?

  • Described solely by its interface contract and behavioral attributes (i.e. hides its implementation and facilitates loose-coupling)

Loose Coupling of Services:

  • Loose coupling is achieved through abstracting and resolving the differences between two or more systems in order to facilitate a seamless integration
  • An ESB/OSB provides or helps to mediate the differences along the following lines:
    1. Transport Protocol
    2. Interaction Pattern (message exchange pattern)
    3. Shape (Interface / Schema)
    4. Security Paradigm

More definition for loose coupling of services:

  • Oracle Service Bus establish loose coupling between service clients and business services
  • OSB maintains the central point security and monitoring
  • Oracle Service bus is an intermediary that processes incoming service request messages, determines routing logic, and transforms these messages for compatibility with other service consumers
  • It receives messages through a transport protocol such as HTTP(S), JMS, File, and FTP, and sends messages through the same or a different transport protocol
  • SOA is a kind of architecture that uses services as building blocks to facilitate enterprise integration and component reuse through loose coupling

Q) Describe OSB’s role as a Message Broker ?

  • A message broker is an architectural pattern for message validation, message transformation and message routing
  • It mediates communication amongst applications, minimizing the mutual awareness that applications should have of each other in order to be able to exchange messages, effectively implementing decoupling

OSB Message broker:

  • Decoupling (via interfaces)
  • Routing: provides routing to the correct service instance according to technical or functional data to take into account the partitioning of the components business applications
  • Message transformation and enrichment
  • Service composition/aggregation
  • Light orchestration (stateless)
  • Version management
  • Protocol break
  • Message validation
  • Error handling
  • Content Control
  • Schema Validation

Q) What are some of the major protocols that OSB supports ?

  • HTTPS
  • SOAP
  • JMS
  • SMTP/POP/IMAP
  • Tuxedo
  • EJB
  • Native MQ
  • File
  • FTP
  • STFP
  • Email

Q) What is meant by Location Transparency ?

  • A service bus is used for endpoint virtualization
  • In 11g stack, Oracle Service Bus (OSB) is the primary service bus
  • So, we can expose proxy service at OSB t0 outside world and in exposed OSB proxy message flow, route incoming request to any business service on the basis of routing logic
  • Note: alternatively, use Mediator in SOA 11g to expose service and use mediator routing logic to route to actual service

OSB Location Transparency:

  • OSB creates “Location Transparency” through isolation of consumers from service providers and act as a proxy layer to transport the message
  • OSB can be used to isolate service location changes

Q) What is Message Enrichment ?

  • Getting additional information from the existing service using Service Callout option
  • And then adding/inserting this additional information (required) into an incoming message/request XML before it route to the service endpoint
  • In OSB 11g, it is Business Service
  • Sometimes, you may have legacy application coded in core Java or EJB, and then at times you may need Java Callout

Q) Explain OSB Service Orchestration ?

  • Combining existing services to make new services
  • This is light orchestration as compared to the BPEL orchestration in SOA which may be Synchronous/Asynchronous
  • But in OSB 11g, it is stateless
  • There are limitations with OSB 11g as compared to the BPEL/SOA which could be used for maintaining states for hours/days as per our business needs

Folks, it’s your turn to comment & suggest for improvement

Note: We have taken inputs from various folks and other weblog for making this comprehensive set of Oracle SOA-OSB interview & answers

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