USe of INTERFACES if_oo_adt_classrun .

1. When you run the application from eclipse, the class name ZCL_ABAP_ADT”your custom class which implements if_oo_adt_classrun” is sent as a parameter to the service “ADT”(from SICF) as a HTTP request.

2. Now the URI of the class that you are running is also important, when we run the class, the URI will be like this: “/oo/classrun/ZCL_ABAP_ADT”, this will be sent from Eclipse I guess.

3. There is a class “CL_OO_ADT_RES_APP”, which has a method : register_resources, this has all the URl patterns and their respective classes., in our case “CL_OO_ADT_RES_CLASSRUN” for our URI from step 2.

4. Now in the above URI matched class method, there is a variable of type if_oo_adt_classrun, which will be instantiated with your custom class type “ZCL_ABAP_ADT” from step1. (check how interfaces works if you don’t understand this step)

5. Now they will call that variable instance method “main”, which holds our custom class instance, so it will call ZCL_ABAP_ADT->main.

Source : link 

2.

When a program is created and need to be transported to production does selection texts always go with it? if not how do you make sure? Can you change the CTS entries? How do you do it?

if you are creating a new program then it will not ask request
for selection texts
and they wiill be automatically included in request and
transported.

If you are modifying an existing program and then if you want
to change selection
text then it will ask for request for text also then save it
in same request and transport.

What is CTS

The Change and Transport System (CTS) is a tool that helps you to organize development projects in the ABAP Workbench and in Customizing, and then transport the changes between the SAP Systems and clients in your system landscape.

How do you validate the selection criteria of a report? And how do you display initial values in a selection screen?

The selection criteria is validated in the processing block of the AT SELECTION SCREEN event for the input values on the screen and respective messages can be sent

 

In an ABAP^TM program how do you access data that exists on presentation server vs. on an application server?

For presentation server use UPLOAD or WS_UPLOAD function modules.
For application server use OPEN DATASET, READ DATASET and CLOSE DATASET command

What are presentation and application servers in SAP®?

Presentation Server is the system with GUI where the
enduser works
Application server is where the dispatcher distribute the
work load to the different work processes(like Dailog
wp,B/G wp,spool wp, update wp and enque wp )and makes the
job done.

Database Server is where it contains three buffer( D/B
buffer,SQL buffer and Redolog buffer )and a Actual data
base where the commited data is stored.

How do you number pages in SAP script layout outputs?

&PAGE& – current page.

&SAPSCRICT-FORMPAGES&- total number of pages.