Java quiz 28: Object values as parameters

  Quizzes     Assignments     Puzzles     Easy exercises     Required knowledge  
< Java Quizzes    Green = Easy,  Blue = Normal,  Red = Hard
Select    01   02   03   04   05   06   07   08   09   10   11   12   13   14   15 
 16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   By title 
>

Java quiz 28: Object values as parameters

Level: Normal

What is the output of the following code?

public class MyClass
{
  static void myMethod(StringBuffer s1, StringBuffer s2)
  {
    s1.append("h");
    s2.append("k");
    s1 = new StringBuffer("x");
    s2 = s1;
  }
  public static void main(String[] args)
  {
    StringBuffer sb1 = new StringBuffer("m");
    StringBuffer sb2 = new StringBuffer("o");
    myMethod(sb1, sb2);
    System.out.print(sb1 + ", " + sb2);
  }
}
Author: Sar Maroof

a. This program writes “mh, ok” to the standard output.
b. This program writes “mx, ox” to the standard output.
c. This program writes “h, k” to the standard output.
d. This program writes “m, o” to the standard output.
e. This program writes nothing to the standard output.
f. Runtime exception.
g. This code fails to compile.

Answer explanation

We actually passed the values of the objects sb1 and sb2 not their references to the method myMethod, Therefore,
the statements
s1 = new StringBuffer(“x”); and s2 = s1; don’t affect the output of the program.

The correct answer is: a.





Sar Maroof is a professional software development teacher, gives master classes and publishes technical articles. He is also an expert software developer and worked for several big as well as small companies and later as a freelancer.

 Subscribe to Sar Maroof's RSS feeds!
 Mail this page to a friend!
 Bookmark this page!

Leave a Reply

Your email address will not be published. Required fields are marked *