STUDENT DATA:

• NAME: __________________________________

• ID#: _____________________________________

• SECTION#: ________________________________

1. (20 points):

You have been given a design document for a veterinary registration system for implementation in Java. It states: "A pet has an owner, a registration date, and a vaccination-due date. A cat is a pet that has a flag indicating if it has been neutered, and a textual description of its markings." Given that the Pet class has already been defined and you expect the Cat class to be used freely throughout the application, please answer the following questions:

• How would you make the opening declaration of the Cat class, up to but not including the first opening brace? Use only these words and spaces: boolean, Cat, class, Date, extends, Object, Owner, Pet, private, protected, public, String.
• Answer:

  	________________________________________________________________________
  	

• Cirlcle which of the following fields would be appropriate for inclusion in the Cat class as members?

  A.	Pet thePet;
  B.	Date registered;
  C.	Date vaccinationDue;
  D.	Cat theCat;
  E.	boolean neutered;
  F.	String markings;

2. (20 points):

What will happen when you try to compile the following code?

    public void printArray(Object x) {
	if (x instanceof int[]) {
	    int[] n = (int[]) x;
	    for (int i = 0; i < n.length; i++) {
		System.out.println("integers = " + n[i]);
	    }
	}
	if (x instanceof String[]) {
	    System.out.println("Array of Strings");
	}
    }
    

(Circle all correct answers.)

A.	It compiles without error.
B.	The compiler objects to line 2 comparing an Object with an array.
C.	The compiler objects to line 3 casting an Object to an array of int primitives.
D.	The compiler objects to line 7 comparing an Object to an array of Objects.

3. (20 points):

The GenericFruit class declares the following method to return float number of calories in the average serving size:

    public float aveCalories()
    

Your Apple class, which extends GenericFruit, overrides this method. In a DietSelection class that extends Object, you want to use the GenericFruit method on an Apple object. What is the correct way to finish the statement in the following code fragment so the GenericFruit version of aveCalories is called using the gf reference?

    GenericFruit gf = new Apple();
    float cal = // finish this statement using gf
    

(Circle the correct answer.)

A.	gv.aveCalories();
B.	((GenericFruit) gf).aveCalories();
C.	gf.super.aveCalories();
D.	There is no way to call the GenericFruit method

4. (20 points):

How many String objects are created in the following code?

    String a, b, c;
    a = new String("1234");
    b = a; c = a + b;
    

(Circle the correct answer.)

A.	One
B.	Two
C.	Three
D.	Four

5.(20 points):

Create a program SwapChar that takes a string and two integers as command-line arguments. The program should print out a modified string obtained from the original string by swaping two characters at positions specified by the two integers. For example, suppose that you enter the following:

    java SwapChar oat 0 2

The program should display

    tao

and exit. In addition, your program should catch and handle all exceptions that might arise because of a bad input. Each type of exception should be handled independently, by printing an appropriate error message which would specify what exactly was wrong with the input. Hint: please remember that invalid array access causes ArrayIndexOutOfBoundsException. You might also find useful some of the following methods:

    public static int java.lang.Integer.parseInt(String s)
	    throws NumberFormatException;
    public char java.lang.String.charAt(int index)
	    throws IndexOutOfBoundsException;
    public void java.lang.StringBuffer.setCharAt(int index, char c)
	    throws IndexOutOfBoundsException;
    public java.lang.StringBuffer java.lang.StringBuffer.append(char c);
    

Please continue your answer on the other side of page 3 --->

Good Luck !