Below are some of the important concepts in Object oriented ABAP. Since OO ABAP is foundation for the latest offerings in ABAP ( Including Restful ABAP ) it is very much required in ABAP and below are some of the concepts which can be asked in interview. Kindly click on the below links to know more  about each topics
  1. Data Declaration in ABAP ( new syntax ) Click Here.
  2. Internal table in ABAP Click Here.
  3. Introduction to Object Oriented ABAP ( Basics )  Click Here.
  4. Enhancement Framework ( BADI’s ) Click Here.
  5. Exceptions Handling in ABAP Click Here.
  6. Basic Concepts on Classes in ABAP Click Here.
  7. Narrow and Wide Casting in ABAP Click Here.
  8. Singleton Classes in ABAP Click Here.
  9. Core Data Services ( CDS Views ), Association and Composition Click Here.
  10. ABAP Database Connectivity ( ADBC ) Click Here.
  11. Basics of BRF Click Here.
  12. New Syntax in OO ABAP and points to keep in mind Click Here.
  13. MVC Architecture in ABAP Click Here.
  14. Persistent Objects in ABAP Click Here.
  15. Friend Classes in ABAP Click Here.
  16. Object Oriented ALV’s in ABAP Click Here.
  17. Business Transaction Events ( BTE’s ) Click Here.
  18. Web Services in ABAP Click Here.
  19. Switch in ABAP Click Here.
  20. New ABAP Syntax-Points to keep in mind Click Here.
  21. User Exits and Customer Exits in ABAP Click Here.
  22. DDIC Structures and ALV Reports Interview Questions Click Here.
  23. New ABAP syntax Basics Click Here.
  24. How to create BADI an example Click Here.
  25. CDS interview Questions Click Here.
  26. Dynamic Programming Click here.
  27. Business partner Configuration in SAP Click Here.
  28. Stateful vs Stateless Click Here.
  29. ‘me’ variable in ABAP Click Here.

Classical ABAP Concepts

Below are some of the basic terminologies in sap and if you have ever given an interview you will know that these basic terminologies must be very clear before you go for an interview.  Please click on the link to know more about each of the mentioned topics:-

1. Different parts of a report in ABAP Click Here.
2. ALV ( ABAP List Viewer ) in ABAP Click Here.
3. Miscellaneous topics in ABAP Click Here.
4. BDC ( Batch Data communication ) in ABAP Click Here.
5. BAPI’s in ABAP Click Here.
6. Module Pool Programming in ABAP Click Here.
7. DDIC Structures and ALV Reports Click Here.
8. ABAP on HANA Click Here.
9. OData Click Here.

Some more classical concepts

  1.  Internal table declaration and operations Click Here.