ARTICLE
Abstract and Final Methods and Classes
Using the ABSTRACT and FINAL additions of
the METHODS and
CLASS statements, you can define abstract and final methods
or classes.
Abstract methods are declared in abstract classes and cannot be
implemented in the same class but only in a subclass of the inheritance
tree. Abstract classes can consequently not be instantiated. A
non-abstract method is a concrete method. Except for the instance
constructor, the concrete instance methods of a class can also call its
abstract methods.
Final methods cannot be redefined in subclasses. Final classes cannot
have any more subclasses and constitute the final node of an inheritance
tree.
Note
In classes that are abstract and final at the same time, only the static
components can be used. Instance components can be declared, but these
cannot be used. For this reason, it is recommended that you specify both
ABSTRACT and FINAL only for
static classes .
Documentation extract taken from SAP system, � Copyright SAP AG. All rights reserved