ExamLab Question.

[Pritha Banerjee]

Given the following code fragment:

import java.util.*;
  public class Gencs{
    public static void main(String args[]){
      String b="fAlSe";
      String s1=null,s2=null;
      s1=new Formatter().format("%b",b).toString();
      s2=new Formatter().format("%b",new Boolean(b)).toString();
      System.out.println(s1+" "+s2);
    }
  }

For any non null argument, %b returns true. So in line 6 we get true. However in line 7 'format("%b",new Boolean(b)).toString();' returns false. Please explain.

[Piet Souris]

Pritha Banerjee wrote:
For any non null argument, %b returns true.

No. Have a look at the API of the class Formatter, especially what it says about the %b conversion.
When the argument is not null, then it makes a discrimination between a boolean argument and a non-boolean.

Nasty trick-questions...

[Pritha Banerjee]

'For "%b" : If the argument arg is null, then the result is "false". If arg is a boolean or Boolean, then the result is the string returned by String.valueOf(). Otherwise, the result is "true".' I got it, thanks Piet