Wrapper Class

[deshdeep divakar]

This is a Question from Danch

import java.io.*;
 
class booleanchk
{
public static void main(String [] args)
{
 
    Boolean b1 = Boolean.valueOf(true);
    Boolean b2 = Boolean.valueOf(true);
    Boolean b3 = Boolean.valueOf("TrUe");
    Boolean b4 = Boolean.valueOf("tRuE");
    System.out.print((b1==b2) + ",");
    System.out.print((b1.booleanValue()==b2.booleanValue()) + ",");
    System.out.println(b3.equals(b4));
 
}
}  

According to me the Output should be:false,true,true.becoz valueOf();
method is just another way to construct wrapper object,and when we compare
two different object references it returns false.While the idea i have got
from the explanation of Question is their is a huge difference between
saying:

Boolean b1=new Boolean(true);
and Boolean b2=Boolean.valueOf(true);
the previous one allocates memory for the object and returns a reference variable b1 which will point to the newly constructed Boolean wrapper class
object on heap.whether the later one valueOf() method just returns a reference variable b2 to either Boolean.FALSE or Boolean.TRUE.

But Still the thing left dangling is,is'nt both the objects are different.
plz elobrate on to this as soon as possible.

Thanks
Java Man
Deshdeep

[deshdeep divakar]

Hi,
All Ranchers have a close look to this code

import java.io.*;
 
class E
{
  public static void main (String[] args)
{
    Byte b1 = new Byte("1"), b2 = new Byte("1");
    System.out.println((b1==b2)+","+(b1.equals(b2)));
Byte b3=Byte.valueOf("1");
Byte b4=Byte.valueOf("1");
System.out.println((b3==b4)+","+(b3.equals(b4)));

Boolean b11 = Boolean.valueOf(true);
    Boolean b22 = Boolean.valueOf(true);
    Boolean b33 = Boolean.valueOf("TrUe");
    Boolean b44 = Boolean.valueOf("tRuE");
    System.out.println((b11==b22) + ",");
    System.out.println((b11.booleanValue()==b22.booleanValue()) + 
 
",");
    System.out.println(b33.equals(b44));

}
}  

Output:
false,true
false,true
true,true,true
whether according to me
Output:
false,true
false,true
false ,true,true
which is coz we r comparing two different object references via ==
plz elobrate to this...

[parimelazhagan vinayagam]

Hi,
Bolleans true and false are stored in literal pools...so there will be only two values...that never get change. and references are pointing to these values only..Depends on the value,it will point to either false or true..so the results...


Thanks
Pari