• 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:
  • Campbell Ritchie
  • Jeanne Boyarsky
  • Ron McLeod
  • Paul Clapham
  • Liutauras Vilda
Sheriffs:
  • paul wheaton
  • Rob Spoor
  • Devaka Cooray
Saloon Keepers:
  • Stephan van Hulst
  • Tim Holloway
  • Carey Brown
  • Frits Walraven
  • Tim Moores
Bartenders:
  • Mikalai Zaikin

Shadowing of reference variables

 
Ranch Hand
Posts: 67
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hello,

Kindly look at the following program and explain why the fourth line in output is 99 instead of 420

Output
-----------
f.myBar.barNum is 28
myBar.barNum in changeIt is 99
myBar.barNum in changeIt is now 420
f.myBar.barNum after changeIt is 99

Thanks
Vivek.
 
Sheriff
Posts: 14691
16
Eclipse IDE VI Editor Ubuntu
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Please UseCodeTags the next time you post some code.
 
Christophe Verré
Sheriff
Posts: 14691
16
Eclipse IDE VI Editor Ubuntu
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
In changeIt, myBar = new Bar(); is assigning a new instance to the method parameter myBar, not to the instance variable. myBar.barNum = 99 sets the instance variable to 99, because the instance variable was passed to the method (i.e. method parameter = instance variable).
 
Christophe Verré
Sheriff
Posts: 14691
16
Eclipse IDE VI Editor Ubuntu
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
You can see that the instance variable doesn't change by outputting its value :
 
reply
    Bookmark Topic Watch Topic
  • New Topic