Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Ron McLeod
  • Rob Spoor
  • Tim Cooke
  • Junilu Lacar
Sheriffs:
  • Henry Wong
  • Liutauras Vilda
  • Jeanne Boyarsky
Saloon Keepers:
  • Jesse Silverman
  • Tim Holloway
  • Stephan van Hulst
  • Tim Moores
  • Carey Brown
Bartenders:
  • Al Hobbs
  • Mikalai Zaikin
  • Piet Souris

Strange Behaviour Of Wrapper Class

 
Greenhorn
Posts: 14
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Report post to moderator
Hello EveryOne,

I was just playing around the wrapper classes and observed some unexpected behaviour.

public class HelloWorld
{
public static void main( String args[] )
{
Integer i1 = 100;
Integer i2 = 100;

System.out.println( "i1 == i2 : " + ( i1 == i2 ) );
}
}

Output of the above code is unexpected with different values of i1 and i2.

For the current values ( i1 = 100 and i2 = 100 ) the output is : "i1 == i2 : true"

But for the following code,

public class HelloWorld
{
public static void main( String args[] )
{
Integer i1 = 1000;
Integer i2 = 1000;

System.out.println( "i1 == i2 : " + ( i1 == i2 ) );
}
}

the output is "i1 == i2 : false"

From different conbinations I have observed that in the above code for values of i1 and i2 between -128 to 127 ( range of byte ), i1 == i2 evaluates to true and for other values i1 == i2 evaluates to false.

What could be the reason behind this behaviour?

Thank You,
Sanket Meghani.
 
Rancher
Posts: 3742
16
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Report post to moderator
Check out this post.

Specifically the discussion that follows on from the first paragraph in Ken Blair's first post.
[ August 03, 2007: Message edited by: Joanne Neal ]
 
Ranch Hand
Posts: 1970
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Report post to moderator
Cross-post. Also posted in Advanced, and answered there (initially by me).
 
Consider Paul's rocket mass heater.
    Bookmark Topic Watch Topic
  • New Topic