Win a copy of Rust Web Development this week in the Other Languages forum!
  • Post Reply 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:
  • Tim Cooke
  • Campbell Ritchie
  • Ron McLeod
  • Liutauras Vilda
  • Jeanne Boyarsky
Sheriffs:
  • Junilu Lacar
  • Rob Spoor
  • Paul Clapham
Saloon Keepers:
  • Tim Holloway
  • Tim Moores
  • Jesse Silverman
  • Stephan van Hulst
  • Carey Brown
Bartenders:
  • Al Hobbs
  • Piet Souris
  • Frits Walraven

immutable?????????

 
Ranch Hand
Posts: 481
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
we know that strings are immutable.

then how come in the following code s1 prints 3

public class Test
{

public static void main (String[] args)
{
String s1 = "1";
String s2 = "2";
String s3 = s1;
s1="3";
System.out.println(s1+s2+s3);/////
}
}
 
Greenhorn
Posts: 4
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Strings are immutable,but what we're talking about here is the String object. s1 is a reference,and can obviously point to any String object.
 
lowercase baba
Posts: 13018
66
Chrome Java Linux
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
What you are doing here is telling the JVM to create a brand new string "3", and change s3 to refer to it. the original string that s3 USED to refer to hasn't changed... if you print s1, it'll still print "1".

in other words, you can chage what string a reference points to, you can create new string, but you CAN'T change an old string.
 
Greenhorn
Posts: 26
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
public class TimDig extends TimDigSuper{
//String device = "Mobile.device";
public static void main(String[] args) {
String s1 = new String("D");
String s2 = "2";
String s3 = s1;
s1.toLowerCase();
System.out.println(s1+s2+s3);/////
}


}
Try this and see ur doubt will be cleared as what immuteable means.
cheers,
Santu.
 
Ranch Hand
Posts: 63
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi there
Just a doubt.
Does the output for the above code is "321"..
regards
Balaji.S
 
Greenhorn
Posts: 29
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
try run it... but yes it gives 321
 
Greenhorn
Posts: 29
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Ya the output is 321 but what is being asked for is just s1, which is 3 only
 
You showed up just in time for the waffles! And this tiny ad:
Building a Better World in your Backyard by Paul Wheaton and Shawn Klassen-Koop
https://coderanch.com/wiki/718759/books/Building-World-Backyard-Paul-Wheaton
reply
    Bookmark Topic Watch Topic
  • New Topic