BIT 2204  OBJECT ORIENTED PROGRAMMING II KCA Past Paper

UNIVERSITY EXAMINATIONS: 2010/2011
SECOND YEAR EXAMINATION FOR THE DEGREE OF BACHELOR OF
SCIENCE IN INFORMATION TECHNOLOGY
BIT 2204: OBJECT ORIENTED PROGRAMMING II
DATE: AUGUST 2011 TIME: 2 HOURS
INSTRUCTIONS: Answer question ONE and any other TWO questions

Question One
a) Differentiate between Applet and Application as used in Java programming (4 Marks)
b) List Four reason that explain why Java programming is popular (4 Marks)
c) Describe FOUR components implemented in JVM (8 Marks)
d) Differentiate the functional differences between Bycode verifier and the class loader as used in
Java programming (4 Marks)
e) When an object is created, instance variables are initialized with their respective default values.
What are the default values for the following instance types?
i. Byte
ii. Int
iii. Float
iv. Char (4 Marks)
f) With examples Differentiate between type promotion and type casting (4 Marks)
g) Give the output of the above program
class RelationalOpSample {
public static void main ( String args[] ) {
int num1 = 10, num2 = 30;
System.out.println( num1 + “==” + num2 + ” = ” + ( num1== num2));
System.out.println( num1 + “!=” + num2 + ” = ” + ( num1!= num2));
System.out.println( num1 + “>=” + num2 + ” = ” + ( num1>= num2));
System.out.println( num1 + “<=” + num2 + ” = ” + ( num1<= num2));
}
} (2 Marks)
Question Two
a) Predict the output of the following program
import java.io.*;
class InputSample1 {
public static void main ( String args[] ) throws IOException {
BufferedReader br = new BufferedReader(
new InputStreamReader( System.in));
String str;
int i=0;
int sum = 7;
System.out.println(“Current Total = ” + sum );
System.out.print(“Enter a number : “);
str = br.readLine();
try {
i = Integer.parseInt(str); // convert from String to integer
} catch ( NumberFormatException e ) {
System.out.println(“invalid format”);
}
sum = sum + i;
System.out.println(“\nNew Total = ” + sum);
} (4 Marks)
b) Describe with examples the syntax of the following program flow controls and advice when to use
them
i. While
ii. Do while
iii. Endless/finite for control construct (9 Marks)
c) Describe the following flow stubs
i. Continue
ii. Break
iii. Label (6 Marks)
d) Give two rules used when naming variables (1 Mark)
Question Three
a) What is the relevance of the following keywords as used Java Programming? Give examples to
support your answer.
i. new
ii. extends
iii. implements
iv. throws (8 Marks)
b) Create a class named Sweets. Its main() method holds an integer variable named numberofSweets
to which you will assign a value. Create a method to which you pass numberofSweets. The method
displays the sweets in dozens. For example, 40 sweets is 3 dozens and 4 left over. (6 Marks)
c) Create a class named Shirt with data fields for collar size and sleeve length. Include a constructor
that takes arguments for each field. Also include a String class variable named material and
initialize it to “cotton”. Write a program TestShirt to instantiate 3 Shirt objects with different collar
sizes and sleeve lengths, and then display all the data, including material, for each shirt. (6 Marks)
Question Four
a) Copy and complete the following table about access modifiers (The first one has been done as an
example) (6 Marks)

b) Interfaces are quite useful in programming (Java). Explain Four uses of interfaces (4 Marks)
c) Explain the meaning of the following keywords
i. Final
ii. Instanceof (4 Marks)
Question Five
a) Create a class named Student. A Student has fields for an ID number, number of credit hours
earned, and number of points earned. (For example, many schools compute grade point averages
based on a scale of 4, so a three-credit-hour class in which a student earns an A is worth 12 points.)
Include methods to assign values to all fields. A Student also has a field for grade point average.
Include a method to compute the grade point average field by dividing points by credit hours
earned. Write methods to display the values in each Student field.
b) Write a class named ShowStudent that instantiates a Student object from the class you created.
Compute the Student grade point average, and then display all the values associated with the
Student.
c) Create a constructor method for the Student class you created. The constructor should initialize
each Student’s ID number to 9999 and his or her grade point average to 4.0. Write a program that
demonstrates that the constructor works by instantiating an object and displaying the initial values.
(20 Marks)

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