s kumar <sudhir.ku@gmail.com> wrote:

The  point of the keyword "abstract" is to demand that a class be extended,
and that programs use only one of the derived classes.  This forces a
programmer to derive a class from the abstract class in order to use it (not
counting static members, of course).

It is part of the rules of the Java language that one cannot instantiate an
abstract class.  This enforces the "you must extend this class" rule.