Table of contents
Preface
This module is part of a self-assessment test designed to help you determine how much you know about object-orientedprogramming using Java.
The test consists of a series of questions with answers and explanations of the answers.
The questions and the answers are connected by hyperlinks to make it easy for you to navigate from the question to the answer and back.
I recommend that you open another copy of this document in a separate browser window and use the links to under Listings to easily find and view the listings while you are reading about them.
Questions
Question 1 .
What output is produced by the program shown in Listing 1 ?
- A. Compiler Error
- B. Runtime Error
- C. Joe Joe false
- D. Joe Joe true
- E. None of the above.
| Listing 1 . Listing for Question 1. |
|---|
public class Ap141{
public static void main(String args[]){new Worker().doIt();
}//end main()}//end class Ap141
class Worker{void doIt(){
char[]anArray = {'J','o','e'};
String Str1 = new String(anArray);String Str2 = new String(anArray);
System.out.println(Str1 + " " + Str2 + " " +
(Str1 == Str2));}//end doIt()
}// end class Worker |
Question 2
What output is produced by the program shown in Listing 2 ?
- A. Compiler Error
- B. Runtime Error
- C. Joe Joe false
- D. Joe Joe true
- E. None of the above.
| Listing 2 . Listing for Question 2. |
|---|
public class Ap142{
public static void main(String args[]){new Worker().doIt();
}//end main()}//end class Ap142
class Worker{void doIt(){
char[]anArray = {'J','o','e'};
String Str1 = new String(anArray);String Str2 = new String(anArray);
System.out.println(Str1 + " " + Str2 + " " +
Str1.equals(Str2));}//end doIt()
}// end class Worker |
Question 3
What output is produced by the program shown in Listing 3 ?
- A. Compiler Error
- B. Runtime Error
- C. ABC DEF GHI
- D. None of the above.
| Listing 3 . Listing for Question 3. |
|---|
public class Ap143{
public static void main(String args[]){new Worker().doIt();
}//end main()}//end class Ap143
class Worker{void doIt(){
java.util.ArrayList ref =new java.util.ArrayList(1);
ref.add("ABC ");ref.add("DEF ");
ref.add("GHI");System.out.println((String)ref.get(0) +
(String)ref.get(1) +(String)ref.get(2));
}//end doIt()}// end class Worker |
Question 4
What output is produced by the program shown in Listing 4 ?
- A. Compiler Error
- B. Runtime Error
- C. ABC DEF GHI
- D. None of the above.
| Listing 4 . Listing for Question 4. |
|---|
public class Ap144{
public static void main(String args[]){new Worker().doIt();
}//end main()}//end class Ap144
class Worker{void doIt(){
ArrayList ref =new ArrayList(1);
ref.add("ABC ");ref.add("DEF ");
ref.add("GHI");System.out.println((String)ref.get(0) +
(String)ref.get(1) +(String)ref.get(2));
}//end doIt()}// end class Worker |