Java quiz 14: Comparing strings

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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.





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.

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