In JAVA please Use the following code fragments for the next 3 questions. Assume

Question

In JAVA please

Use the following code fragments for the next 3 questions. Assume that:

Student, Employee, and Retired are all child classes of Person

All four classes have different implementations of a method called getMoney

Person p1 = new Person(...);

int m1 = p1.getMoney(); // statement1

Person p2 = new Student(...);

int m2 = p2.getMoney(); // statement2

Person p3;

if(m2 < 100000) {

p3 = new Employee(...);

} else {

p3 = new Retired(...);

}

int m3 = p3.getMoney(); // statement3

Question 1

The call to getMoney() in statement1 will invoke the method defined in which class?

Select one:

Person

Student

Employee

Retired

none of the above; this cannot be determined by examining the code

Question 2

The call to getMoney() in statement2 will invoke the method defined in which class?

Select one:

Person

Student

Employee

Retired

none of the above; this cannot be determined by examining the code

Question 3

The call to getMoney() in statement3 will invoke the method defined in which class?

Select one:

Person

Student

Employee

Retired

none of the above; this cannot be determined by examining the code

Explanation / Answer

This questions are of type of Method overriding which is part of dynamic Polymorphism in Java. in case of method overriding child class's method is being invoked.

Person p1 = new Person() // Person as a reference and Person as a object

Person p2 = new Student() // Person as a reference and Student as a object. p2.getMoney is method overriding and it will invoke student's getMoney method

Q -1

Answer : Person , Reason : here the object is instantiated using new Person() so , Person's getMoney is being called

Q-2

Answer: Student , Reason : here the object is instantiated using new Student() , so method overriding is being applied when call to getMoney () , so it will call the getMoney method of Student()

Q-3

None of the above, can not be determited by examining code, Reason : here we are not sure how p3 object is being intialized since if m<100000 then employee's getMoney will be called else Retired's getMoney is being called. So from code we are not sure which getMoney is being called it depends on m's value.

More info about oop in method overriding : https://stackoverflow.com/questions/20783266/what-is-the-difference-between-dynamic-and-static-polymorphism-in-java

Hope it is clear :)

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