HGrid or Hierarichal Grid is most complex bean available in OAF which is used to represent hierarichal data along with details at every node.

There are some scenarios where we need to take some action on the basis of LOV, LOV fires three events:
1) lovUpdate : when user selects a value from lov.
2) lovValidate: when user enters a valid value in the lov input and tabs out then lov doesn't get pop-up.
In this case lovValidate event is fired.
3) lovPrepare: when user clicks on torch icon: "lovPrepare" event is fired.

OA Framework provides the ConcurrentRequest class to call the concurrent program from the page, it resembles with its counterpart FND_REQUEST.SUBMIT_REQUEST in PL/SQL.
The submitRequest() method in the ConcurrentRequest class takes 6 parameters and returns request id of the submitted concurrent request, every thing is same as fnd_request.submit_request the only difference is in mechanism to pass Concurrent Program specific Parameters, in PL/SQL we used argument1 to 100 here we are using vector:

This is a kind of Master Detail Page which displays Details in Hide Show Region but for this we need not to create any Hide Show Region.

Sometimes we need to control the Visual Properties like font size, color etc, then we used to set property manually either through code or by creating our own custom classes.

Oracle Payables shares purchase order information from purchasing module which enables online matching with invoices. Invoiced or billed items are matched to the original purchase orders to ensure that we’ll pay only for the goods or services we ordered and/or received. If we are billed for an item over the amount and quantity tolerances we defined in the Invoice Tolerance window, during Approval, Oracle Payables applies a hold to the invoice, which prevents payment.