Polymorphism is a Problem

class Drawable { abstract void draw(); } abstract class Shape extends Drawable {} class Circle extends Shape { void draw() { printf("Circle"); } } class Triangle extends Shape { void draw() { printf("Triangle"); } } class Rectangle extends Shape { void draw() { printf("Rectangle"); } } class Square extends Rectangle {} and it is associated with an instantiated class (i.e., it is the method that will be executed for objects of that class). In reachability terms, a method implementation may be executed if it can be reached from the program entry point(s) via both an ‘invocation’ path and an ‘instantiation’ path. Abstractly, the reachability problem is a conjunction of paths.