Question

Given the following code, find the compile error.

Answer 1

Answer:

a. Object cannot be converted to Person

Explanation:

This program demonstrates polymorphism.

e.g., a Student IS a Person therefore you can call m() with a Student as well as a Person object.

The same goes for GraduateStudent.

However, and Object is not a Person, so the last call fails. This can be deducted by the type checking that happens at compile time.