OAF Interview Questions
What is the pattern used in developing any OAF component?
MVC (Model, View, Controller)
Lists the components in the MVC architecture?
Model: Application Module, View Objects, View Links, Entity Objects, Entity Associations etc.
View: Page, Region, Attributesets etc.
Controller: Controller class files
Which is the component responsible for user actions?
Controller is the object. The code present in ProcessFormRequest gets executed up on the user action.
If we have to initialize something during the page loading, which is the right place?
ProcessRequest() method of the Controller file is the right place.
What is the significance of ProcessFormData()?
For a ‘POST’ request the data on the page is binded to the view object in this method
Does ‘GET’ request result in calling ProcessFormData()?
No, only POST request calls that.
What is the main Controller component in OAF?
OAController is the main class and our controller will become subclass of it.
How does page structure get created at runtime?
OAPageBean is responsible for creating the bean hierarchy structure at runtime after calling ProcessRequest() of each of the beans in the hierarchy.
What is BC4J and what are all the components of BC4J?
Business Components for Java is JDeveloper's programming framework for building multi-tier database applications from reusable business components. Such applications typically consist of:
- A client-side user interface written in Java and/or HTML.
- One or more business logic tier components that provide business logic and views of business objects.
- Tables on the database server that store the underlying data.
Components of BC4J:
Entity Object - EO encapsulates the business logic and rules. EO’s are used for Inserting, Updating and Deleting data. This is used for validating across the applications.
View Object - View object encapsulates the database query. It is used for selecting data. It provides iteration over a query result set. VO’s are primarily based on EO’s. It can be used on multiple EO’s if the UI is for update.
Application Module - Application Modules serve as containers for related BC4J components. The pages are related by participating in the same task. It also defines the logical data model and business methods needed.
What is an EO?
EO encapsulates the business logic and rules. EO’s are used for Inserting, Updating and Deleting data. This is used for validating across the applications. We can also link to other EO’s and create a Association object.
What is an VO?
View object encapsulates the database query. It is used for selecting data. It provides iteration over a query result set. VO’s are primarily based on Eo’s. It can be used on multiple EO’s if the UI is for update. It provides a single point of contact for getting and setting entity object values. It can be linked together to form View Links.
What is an AO?
An association object is created where we link EO’s. For example take the search page where we link the same EO to form a association between the manager and employee. Every employee should have a manager associated. But if it President then no there is no manager associated. This is a perfect example to understand the AO.
What is an VL?
A view link is an active link between view links. A view link can be created by providing the source and destination views and source and destination attributes. There are two modes of View link operation that can be performed. A document and Master/Detail operation.
What is UIX?
UIX is an extensible, J2EE-based framework for building web applications. It is based on the Model-View-Controller (MVC) design pattern, which provides the foundation for building scalable enterprise web applications.
Which package should include EO and AO?
The EO and AO will be present in the schema.server package.
What is the difference between inline lov and external lov?
Inline lov is a lov which is used only for that particular page for which it was created and cannot be used by any other page.
External lov is a common lov which can be used by any page. It is a common component for any page to use it. It can be used by giving the full path of the lov in the properties section “External LOV” of the item.
What is a Javabean?
JavaBeans is an object-oriented programming interface that lets you build re-useable applications or program building blocks called components that can be deployed in a network on any major operating system platform.
What is query Bean?
QueryBean is used to execute and return the results of a query on behalf of the QueryPortlet application.
What is the difference between auto-customization criteria and result based search?
Results based search generates search items automatically based on the columns on the results table.
In Auto-customization search we need to set what all fields are required to display as a search criteria.
What is MDS?
MDS is MetaData Service. When a web page is broken into small units like buttons,fields etc they are stored in a database. These are not stored as binary files but as data in tables. The data are present in JDR tables. MDS provides service to store & return page definitions. MDS collects those definitions in components/fields in a meaningful manner to build a page.
What is XML?
XML is a markup language for documents containing structured information.
Structured information contains both content (words, pictures, etc.) and some indication of what role that content plays (for example, content in a section heading has a different meaning from content in a footnote, which means something different than content in a figure caption or content in a database table, etc.).
What is the difference between customization and extension?
Customization is under direct user control. The user explicitly selects between certain options. Some customization examples include:
- Altering the functionality of an application
- Altering existing UI
- Altering existing business logic
Extension is about extending the functionality of an application beyond what can be done through personalization. Some extensibility examples include:
- Add new functional flows
- Extend or override existing business logic
- New application/module
- New page
- New attribute
- Extend/Override defaults & validations
What is Personalization?
Personalization enables you to declaratively tailor the UI look-and-feel, layout or visibility of page content to suit a business need or a user preference. Some personalization examples include:
- Tailor the order in which table columns are displayed.
- Tailor a query result.
- Tailor the color scheme of the UI.
- Folder Forms
- Forms Personalization
- Oracle Application Framework (OAF)
What is rootAM?
The application module which is associated with the top-level page region (the pageLayout region) is root application module.
Why should we give retainAM=Y?
The AM should be retained whenever you are navigating away from a page and when you know that there is a possibility to come back to the page again and data is to be retained.
Example: Any navigation link that opens in a new page or any navigation which has a back button to come back to the initial page.
kThe AM should not be retained for two independent pages, especially if they have common VOs which fetch different result sets. In such cases, retaining the AM may not remove the cache of VOs and so the result may not be as expected.
What is the significance of addBreadCrumb=Y?
The basic intention of the breadcrumb is to let the user know of the navigation path he took to reach the current page.
How do you find right jdev patch for your oracle application version?
Search in oracle.metalink.com as Jdev with OA Extension.
What are the tools you had used for decompiling java class?
Jad is one of the tool for decompiling the java class