WebSphere ESB interview questions

What kind of questions might be asked when you go for in WebSphere ESB (or) other ESB' developer interviews?

ESBs really play crucial role in the SOA world today and jobs in this area have grown rapidly in the last few  years. So, when you plan to appear for an ESB developer or consultant positions, you might worry what kind of questions the interviewer might ask for.

In this blog, here I have come up with the list of topics or questions where interviewers (including myself) mostly touch upon for testing the candidate’s capability. This is my initial draft. I would add further questions as and when I remember… 

Any suggestions or feedback to improve the content is appreciated. 

Questions on Architecture, Foundations and/or Pre-requisites:

·         Explain or tell about SOA architecture.

·         How do you differentiate between WebServices and SOA?

·         Compare and contrast different approaches of implementing WebServices; JAX-RPC, JAX-WS, REST (JAX-RS).

·         What is the need of an ESB in SOA architecture? What role does it play?

·         List out the capabilities of ESB

·         Explain SCA architecture. How does it vary from SOA architecture?

o       What is service messaging object? How is it different from data object?

o       Briefly explain the service message object structure.

Questions on Development, Tooling Features:

    

• What kind of projects can you create in WID that run on WebSphere ESB runtime?
• What is an Integration Solution? Can you deploy it on server runtime?
• What is mediation module?
• What is an assembly diagram? What all does an assembly diagram will have?
• List out the different bindings available in WID
• Which is the default binding?
• Which binding will you use when you want to communicate between mediation modules?
• What are different categories of primitives available?
• Difference between XSLT and BO Transforms? If you want the transformation in specific order, which one would you use?
• Difference between Service Invoke and Callout
• If you want to invoke another service within a mediation module and retrieve the response within the same flow, which primitive would you use?
• Difference between Fail and Stop primitives? When do you use each?
• Which primitives have this attribute? “Use dynamic endpoint set in message header”
• How do you dynamically change the web service endpoint address?
• What is the correlation context? How is it different from transient context?
• What is the purpose of shared context? When do you use it?
• When do you think you go for custom primitive? How many input and output terminals can custom primitive have? How do you fire the output through output terminals?
• When do you use a data handler? Name the data handlers that you would have used. How to create your own data handler.
• How do you perform serialization and de-serialization of SMO objects to/from native objects?
• When do you use FanIn & Fanout primitives?
• What are shared libraries? How do you implement them? What are advantages.

EAI patterns:

·         What are the service mediator patterns you worked with?

·         Explain service gateway pattern, selector pattern, aggregation pattern etc…

Questions on WebServices:

·         What is purpose of WSDL in WebServices?

·         Explain WSDL structure

·         What are different WSDL binding styles? When do you use each? How does SOAP message structure change in each of scenario? Which is commonly used?

o       Document literal

o       Document literal wrapped

o       Document encoding

o       Rpc literal

o       Rpc encoding

·         Can you refer another WSDL inside a WSDL? If so, are there any challenges.

·         Explain SOAP message structure.

·         How does a SOAP message with attachments look like?

·         Have you worked with XOP or MTOM? Please explain.

·         When do you use SOAP handlers? What are methods to be implemented if you were implementing it?

·         What are different development approaches in WebServices? Top-down vs bottom-up.

·         Compare JAX-RPC vs JAX-WS vs REST. Which one do you normally use?

·         What are advantages of JAX-WS over JAX-RPC?

·         List the files which get generated at client side and/or server side when you work using

o       JAX-RPC approach

o       JAX-WS approach

Questions on JMS/MQ:

·         What are different types of queues?

·         Tell about different messaging styles in JMS. When do you use each?

    o Point-to-point

    o Publish-subscribe

·         Differences between Topics and Queues

·         Tell me the difference between local and remote queues

·         What is an ActivationSpec? When do you use it?

·         How do you invoke an MDB using JMS?

·         How do you configure your local or remote queues in Websphere?

Security:

·    How do you implement a basic authentication in WebServices Import/Export?

·    Have you worked with SSL security i.e. digital certificates?

·    Explain the usage of WS-Security Policy Sets. What are advantages of using Policy Sets

·    Explain the different steps you perform when implementing any one of the above security mechanisms in WebSphere ESB server?

Other Questions:

• What are differences between WID 6.2 and WID 7.0 or IID? How are mediation modules deployed in v6.2 vs v7.0 etc…
• Have you faced any difficulties during your development & how did you overcome them.