... semantics.A class can be abstract, meaning that it cannot have direct instances at run-time. Such a class is aimed asa generalization of other, concrete classes that can have direct instances. ... TextreceptionHours : Text(b)(a)John Smith : PersonObject Space/RuntimeCooking for Dummies : CourseCar Mechanics for Ladies : CourseComputers for Everybody : CourseArthur Burnstorm : TeacherattendsattendsattendsteachesFigure ... ‘‘system calls’’ for actions upon the object space). More precisely, the code in such a detail-level language contains thecontrol-flow constructs, local variables, expressions, and other speci c elements...