Modularization

Lessons in this topic

• Global Classes vs Local ClassesUnderstand when to use global classes and when local classes are enough.
• Reusable Service Class DesignLearn how to design service classes that can be reused across reports, APIs and enhancements.
• FORM vs Method vs Function ModuleWhen to pick each and why FORMs are legacy.
• Function Groups, Update Tasks and IN UPDATE TASKHow update FMs run inside LUWs.
• Parameter Passing: IMPORTING, EXPORTING, CHANGING and RETURNINGDesign clean interfaces for methods, function modules and reusable routines.
• Includes and Program Structure in Classical ABAPUnderstand how includes are used to organize large classical ABAP reports and module pool programs.
• FORM Routines: Legacy but Still ImportantLearn when FORM routines are still used and why modern ABAP prefers methods.
• Function Modules and Function GroupsUnderstand function modules, function groups, global data and where FMs still matter.
• Methods and Classes for Modern ABAP ModularizationLearn why modern ABAP favors classes and methods for reusable business logic.
• Modularization for Unit Testing and Regression SafetyUnderstand how better modularization reduces regression bugs and supports ABAP Unit.

Interview questions covered

• Report crashes because a FORM reads an uninitialised global variable. How do you prevent it?
• How do you design a service layer for a large ABAP application?
• Difference between FORM and METHOD in ABAP.
• When would you use INCLUDE programs?
• What is the cost of many small function-module calls in a loop?
• How do you evolve a legacy function group into a service class without breaking callers?
• What is a Function Module and when is it required?
• Where would you put business logic that must be reused by a report, a Fiori app and a BAPI?
• When should you use a subroutine (FORM), a function module, and a method?

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