Oracle SOA Interview questions and answers

Part-1 : WSDL and XSD interview questions
Question : What is Web Service ?
Answer: Web service is a piece of code which is available on web (internet). That code of piece can be developed in any language (java, .net etc). A client invokes the web service by sending xml message and it wait for xml response (synchronously or asynchronously).

Question: What is WSDL ?
Answer : WSDL stands for Web Services Description Language
WSDL is a document written in XML. The document describes a Web service. It specifies the location of the service and the operations (or methods) the service exposes.

Question: Explain elements/tags of WSDL ?

• Types : A container for abstract type definitions defined using XML Schema
• message - A definition of an abstract message that may consist of multiple parts, each part may be of a different type
• portType - An abstract set of operations supported by one or more endpoints (commonly known as an interface); operations are defined by an exchange of messages
• binding - A concrete protocol and data format specification for a particular portType
• service - A collection of related endpoints, where an endpoint is defined as a combination of a binding and an address (URI)

Question: Difference between Abstract and Concrete WSDL ?
Answer : Abstract WSDL contains only messages and operations. Abstract WSDL is used by SOAP Server.

Where as concrete WSDL contains messages, operations and transport specific information (JMS or Http). This is used by SOAP client.

Question : What is SOAP ?
Answer : SOAP is a simple XML-based protocol to let applications exchange information over HTTP. Or more simply: SOAP is a protocol for accessing a Web Service.

Question : What is XML Schema ?
Answer : An XML Schema describes the structure of an XML document.

Question : Difference between Include and Import in context to XML schema ?
Answer : The fundamental difference between include and import is that you must use import to refer to declarations or definitions that are in a different target namespace and you must use include to refer to declarations or definitions that are (or will be) in the same target namespace.

Question : What is targetNamespace's function?
Answer : <schema xmlns="http://www.w3.org/2001/SchemaXML         targetNamespace="http://www.example.com/name"         xmlns:target="http://www.example.com/name">
The targetNamespace declares a namespace for other xml and xsd documents to refer to this schema. The target prefix in this case refers to the same namespace and you would use it within this schema definition to reference other elements, attributes, types, etc. also defined in this same schema definition.

Part-2: XSL and Transaction interview questions

Question : How to refer another XSL from main XSL file ?

Answer : The <xsl:import> element is a top-level element that is used to import the contents of one style sheet into another.

Note: This element must appear as the first child node of <xsl:stylesheet> or <xsl:transform>. Syntax: <xsl:import href="URI"/>

Question: Why we use Call-template inside XSL ?

Answer : Call-template works similar to the apply-template element in XSLT. Both attach a template to specific XML data. This provides formatting instructions for the XML. The main difference between the two processes is the call function only works with a named template. You must establish a 'name' attribute for the template in order to call it up to format a document.

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
< xsl:call-template name="myTemplate">
< !-- Content: xsl -->
< /xsl:call-template>
< stylesheet>

Question: Difference between XA & Non-XA transaction ?

Answer: Non-XA (Local Transaction): It involves only one resource. When you use Non-XA transaction then you can’t involve multiple resources (different databases, Queues, application servers etc), you can rollback or commit transaction for only one resource. There is not transaction manager for this transaction as we are dealing with only one resource at a time.

XA (Global Transaction): It involves more than one resource (different databases, queues, application servers) all participate in one transaction. It uses two-phase commit to ensure that all resources either all commit or rollback any particular transaction. When you have scenario like you need to connect to two different databases, JMS Queue and application server, in this case you will use XA transaction that means all resource participate in one transaction only.

Question: What is inline schema ?

Answer: Inline schemas are XML schema definitions included inside XML instance documents. Like external schema documents, inline schemas can be used to validate that the instance matches the schema constraints.

Question: what is the use of Pick Activity?

Answer: This activity waits for the occurrence of one event in a set of events and performs the activity associated with that event. The occurrence of the events is often mutually exclusive (the process either receives an acceptance or rejection message, but not both). If multiple events occur, the selection of the activity to perform depends on which event occurred first. If the events occur nearly simultaneously, there is a race and the choice of activity to be performed is dependent on both timing and implementation.

Question: Design patterns in SOA ?

Question: Difference between Synchronous Process and Asynchronous Process ?

Question: Use of Config Plans ?