Conversion Rules for References
ABAP currently uses class and interface variables within
ABAP Objects
. Both are pointers to objects. You can assign values to them in the following combinations:
If the two class references are incompatible, the class of the target field must be the predefined empty class OBJECT.
When you assign a class reference to an interface reference, the class of the source field must implement the interface of the target field.
If two interface references are incompatible, the interface of the target field must contain the interface of the source field as a component.
When you assign an interface reference to a class reference, the class of the source field must be the predefined empty class OBJECT.