Win a copy of Succeeding with AI this week in the Artificial Intelligence and Machine Learning 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 all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Paul Clapham
  • Ron McLeod
  • Liutauras Vilda
  • Junilu Lacar
Sheriffs:
  • Tim Cooke
  • Jeanne Boyarsky
  • Knute Snortum
Saloon Keepers:
  • Stephan van Hulst
  • Tim Moores
  • Tim Holloway
  • Carey Brown
  • Piet Souris
Bartenders:
  • salvin francis
  • fred rosenberger
  • Frits Walraven

* Byte == comparision

 
Greenhorn
Posts: 17
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Why does this give 'False' ?
 
Bartender
Posts: 2205
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
When you call toString() on an object, internally the code creates a new String instance and returns this to the caller; every time you call toString() a new String instance is created.
Since it's a new String object each time, and since the == operator tests if two objects are the *same object*, this test returns FALSE since the two Strings are different objects.
This again highlights the importance of using the equals() method to compare two objects. ONLY use the == operator if you are comparing primatives, OR if reference comparison is what you really want.
Rob
[ January 11, 2002: Message edited by: Rob Ross ]
 
Greenhorn
Posts: 22
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
This is a common mistake I seen made by many of my coworkers (also one I used to make frequently). Strings are objects, and any time you want to compare objects for equality you have to use:
<String>.equals(<String>)
Otherwise, your just comparing the reference of the two objects(i.e. checking to see if the two objects point to the same place in memory [I think that's the right way to word it]).
Only use the == operator to check equality of primatives (i.e. int, long, double, boolean).
--Chris
[ January 12, 2002: Message edited by: Chris Graham ]
 
And then we all jump out and yell "surprise! we got you this tiny ad!"
Two software engineers solve most of the world's problems in one K&R sized book
https://coderanch.com/wiki/718759/books/Building-World-Backyard-Paul-Wheaton
    Bookmark Topic Watch Topic
  • New Topic