Java quiz 14: Comparing strings

<< Java Quizzes   Green = Easy,  Blue = Normal,  Red = Hard
 Q01   Q02   Q03   Q04   Q05   Q06   Q07   Q08   Q09   Q10   Q11   Q12   Q13   Q14   Q15   Q16   Q17   Q18   Q19   Q20   Q21   Q22   Q23   Q24 
 By title 
>>

As a Java programmer you need very often to work with strings. Here is a simple quiz that shows the way Java handles strings.

Java quiz 14: Comparing strings

Level: Normal

What happens when the following program is compiled and run?

public class MyString
{
  public static void main(String[] args)
  {
    String str1 = new String("Java");
    String str2 = new String("Java");
    String str3 = new String("java");
    if(str1 == str2)
    {
      System.out.print("w");
    }
    if(str1.equals(str2))
    {
      System.out.print("x");
    }
    if(str2.equals(str3))
    {
      System.out.print("y");
    }
    else
    {
      System.out.print("z");
    }
  }
}
  Author: Sar Maroof

Select the correct answer.


Answer explanation

  1. The first conditional statement if (str1 == str2) checks whether str1 and str2 are references of the same object, but they are not.
    Therefore the body is not executed and w is not written to the standard output.
  2. The statement if (str1.equals(str2)) compares str1 and str2 whether their contents are equal. That returns true, because the content
    of both statements are Java. So, the letter x is written to the standard output.
  3. The statement if(str2.equals(str3)) compares str2 and str3 whether their contents are equal.That returns false,
    because the content of str2 is Java while the content of str3 is java starts with small letter.
  4. Since the last if statement returns false the else statement is executed and z is written to the standard output.
  5. The program writes xz to the standard output.

The correct answer is: c.

If you found this difficult, you might consider reading my book Java quizmaster for beginners. It is easy to understand, organized to learn Java in 17 days and it guides you to master Java code by solving 105 quizzes and 117 assignments. This book explains each chapter properly before starting with exercises and assignments. It is available on Amazon. See inside the book here!

Please, leave your questions, feedback and suggestions in the comments below!
SarMaroof.com offers a practical method to learn and improve your Java skills. It avoids unnecessary long boring theoretical explanations, but it uses many exercises and quizzes.




Sar Maroof is graduated from HBO Amsterdam “higher professional education” when he already had a bachelor of science degree in Physics.
He is a SUN certified JSP as well as EJB. He has experience with Java since 2001 and worked for several big as well as small companies and later as a freelancer.
He is the author of Java quizmaster and Build a Java application in 7 days.

Books by Sar Maroof

           

 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 *

Sarmaroof © 2017