Last week, we had the author of TDD for a Shopping Website LiveProject. Friday at 11am Ranch time, Steven Solomon will be hosting a live TDD session just for us. See for the agenda and registration link
  • 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
  • Paul Clapham
  • Ron McLeod
  • Jeanne Boyarsky
  • Tim Cooke
Sheriffs:
  • Liutauras Vilda
  • paul wheaton
  • Henry Wong
Saloon Keepers:
  • Tim Moores
  • Tim Holloway
  • Stephan van Hulst
  • Carey Brown
  • Frits Walraven
Bartenders:
  • Piet Souris
  • Himai Minh

Problem: String != String

 
Greenhorn
Posts: 12
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
why for god's sake i get a 'false' for that?



 
Sheriff
Posts: 22649
126
Eclipse IDE Spring VI Editor Chrome Java Windows
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Don't use == for string comparison - use equals instead.
 
Bartender
Posts: 4179
22
IntelliJ IDE Python Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Strings are Objects, and like any object you should use the .equals() method to compare equality:



The == operator compares identity = if the two Strings are the same Object, not if their contents are equal. Assuming a.getClass().getPackage().getName() is supposed to return "java.util" then you show the two Strings are not the same Object even if they have the same contents.
 
Stefan Müllerheim
Greenhorn
Posts: 12
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
thank you for your quick answer!

your answer is in deed my solution.

but why is the answer of



output: class java.lang.String?

don't complain that 'a' is a String?

 
Greenhorn
Posts: 22
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
This whole statment is returning a String object

Because of that you got that result.
 
Author
Posts: 12617
IntelliJ IDE Ruby
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Because when you print something it will call toString() on it. (And I don't know why it would complain that "a" is a string anyway; it wouldn't matter one way or the other, as long as it was an object.)
 
Greenhorn
Posts: 22
MyEclipse IDE Hibernate Postgres Database
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Compare the output of following two statement :




Then read a little about String literal and String literal Pool.
here

I am almost sure you will get a good insight of why it is so.

Regards
Tarun
 
We're all out of roofs. But we still have tiny ads:
free, earth-friendly heat - a kickstarter for putting coin in your pocket while saving the earth
https://coderanch.com/t/751654/free-earth-friendly-heat-kickstarter
reply
    Bookmark Topic Watch Topic
  • New Topic