Local Classes vs Global Classes

Explanation

A local class is defined inside a single ABAP program and is available only in that program. It is useful for organizing report-specific logic such as ALV preparation, screen handling or local validation. A global class is created in the Class Builder and can be reused across multiple reports, enhancements, OData services, background jobs and APIs. The choice depends on reuse and ownership. If logic is needed only in one report, a local class is enough. If the same business rule is needed in multiple places, a global class is better. In modern ABAP projects, global service classes are commonly used for reusable business logic.

Code example

REPORT zlocal_class_demo. CLASS lcl_alv_helper DEFINITION.  PUBLIC SECTION.    METHODS prepare_output      IMPORTING it_data TYPE STANDARD TABLE      RETURNING VALUE(rv_count) TYPE i.ENDCLASS. CLASS lcl_alv_helper IMPLEMENTATION.  METHOD prepare_output.    rv_count = lines( it_data ).  ENDMETHOD.ENDCLASS.

Real project scenario

A report-specific ALV helper can be a local class. But a material validation service used by a report, BAPI wrapper and OData service should be a global class.

Common mistakes

- Creating global classes for one-time local logic. - Keeping reusable business logic inside a local class. - Putting unrelated helper methods in one global class. - Not considering future reuse.

Best practices

- Use local classes for report-specific organization. - Use global classes for reusable services. - Avoid one giant global utility class. - Think about reuse before deciding class type.

Interview angle

A good answer should say local classes are program-specific, while global classes are reusable and suitable for shared business logic.