Question:

(a) Draw out a UML class diagram that captures the following information: An Employee is a kind of Person. An ATM is a kind of Machine. Both an Employee and an ATM can behave as if they were a Cashier, in that it is possible to both withdraw cash from them and deposit cash with them.

(b) Now consider the Person class and the Cashier interface listed below. Write the Java code for an implementation of the Employee class of part 1(a). Do not complete the body of any methods in the Employee class - just place comments to outline the actions that should occur:

public class Person {
public int age;
public int secId_number;
}

public interface Cashier {
public void withdraw(int account_id, int amount);
public void deposit(int account_id, int amount);
}

(c) The Java class for Person in part 1(b) does not illustrate best practice in Java programming.

i. Modify the Person class to make it robust so that it is not possible for negative values of the fields of an instance of Person to be set.

ii. Define a constructor for the Person class that enables an instance to be created with specific age and secId_number values.

iii. Define a constructor for the Employee class that also enables specific age and secId_number values to be set.

iv. What is the difference between declaring a field private and declaring it protected?