Oracle SOA - Interview Questions Part-4
What is singleton Property in SOA?
In the clustered environment when the processing of the message should happen via only one SOA managed server, then the property singleton needs to be defined at the adapter level.
What is a pick activity? Can I have a pick activity with no onMessage branch?
Pick activity picks the messages from service (Source) which has multiple operations or the BPEL process needs to receive the messages from multiple source system. Pick activity should have at least on Message branch.
What is a flow activity? What is a flowN activity and how does it leverages the flow activity?
Flow activity is used, when parallel execution of the flow is needed and to use this property “non blocking invoke should be set as true “at the partner link level and no. of execution of parallel flow is defined and static. Where as in Flown the no. of execution of parallel flow is not static and it is determined during run time.
What do you mean by non-idempotent activity? Which all activities are non-idempotent by default?
Activities like Pick, Wait, receive, reply and checkpoint() are called non-Idempotent activity and during the execution of the process whenever these activities are encountered then it gets dehydrated to the dehydration store.
How can we embed or use a java code in BPEL?
Using JAVA embedding activity in BPEL,Java code can be embedded in BPEL and can be used.
How does pick activity differ from a receive activity?
Pick activity can act as a multiple recieve activity in some business scenarios.If we have two inbound operations and both can trigger the bpel process then we will go with pick activity as we can’t have two recieve activity with create Instance box checked.
How can we make a partner link dynamic?
If we have to send the request to different service which has the same wsdl then dynamic partner link will be used and using addressing schema we can set the endpoint dynamic to send the request to the desired service.
What is a nonBlockingAll property?
Non- blocking invoke is used when Parallel flow needs to be executed where new thread will be created for each invoke a activity and which will execute simultaneously.
What is getPreference property? How do we set it and what advantage it provides?
Hard coding is not a good practice, so to avoid hard coding preference variable can be used and the value of the preference variable is accessed using getPreference().The preference variable value can be changed without re-deploying the code via em console MBean property.
How can we improve the performance of an XSL file?
By avoiding use of various if statements and using choose, and by using for-each group in place of for-each.
How do we handle transactions in BPEL?
Property needs to be defined to start the new transaction/to continue with the same transactions
Property Name: Transaction and if this has value as required then the BPEL process will be continued in the same transaction where as if the value is defined as requiresnew then it will start the new transaction.
What are transient and durable BPEL processes?
Durable:-It is long running process and initiated through a one-way invocation and do incur one or more dehydration points in the database during execution Ex: Asynchronous
Transient:-It is short-lived process, request-response style processes and do not incur dehydration during their process execution Ex: Synchronous.
When u will go for Sync process?
Whenever the services returns the response in few seconds, it is recommended to go for synchronous BPEL process if not the BPEL process should be Asynchronous the reason is calling application can’t proceed further in case of synchronous process.
What is a syncFileRead operation? Is a inbound or a outbound operation? Can my process begin with syncFileRead operation?
When file has to be read in the mid of the BPEL process, then we will use syncFileRead Operation, means some process should initiate the file read process and it is an outbound operation and process can’t begin with Sync File read.
Can we use a File Adapter to get a file without reading its content?
Yes, by selecting the Do not read file content check box in the JDeveloper wizard while configuring the "Read operation."
How to increase performance increase in bpel (Db Adapter/file adapter)?
We can increase the performance by writing indexes and sequences.
(Or) Go to application server --- >Configurations ----- > Change Xml file
Explain error handling in BPEL and what is a error handling framework? How does a error handling framework better than simple error handling in BPEL?
EHF –Whenever any error thrown by the BPEL process/Mediator then EHF will check whether exist in Fault-Bindings.xml files and if so then the action in the Fault-Policy.xml file will be taken and if the action is not found then the fault will the thrown and it will be handled in the catch block.
How do we resubmit a faulted process?
Scenario A: The BPEL code uses a fault-policy and a fault is handled using the “ora-human-intervention” activity, then the fault is marked as Recoverable and the instance state is set to “Running”.
Scenario B: The BPEL code uses a fault-policy and a fault is caught and re-thrown using the “ora-rethrow-fault” action, then the fault is marked as Recoverable and the instance state is set to “Faulted”; provided the fault is a recoverable one (like URL was not available).
Predefined errors in BPEL?
· Custom errors
· Timed out errors
· BPM errors
· Validation Errors
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