• 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
  • Tim Cooke
  • Jeanne Boyarsky
  • Liutauras Vilda
Sheriffs:
  • Frank Carver
  • Henry Wong
  • Ron McLeod
Saloon Keepers:
  • Tim Moores
  • Frits Walraven
  • Tim Holloway
  • Stephan van Hulst
  • Carey Brown
Bartenders:
  • Al Hobbs
  • Piet Souris
  • Himai Minh

Practice Question

 
Greenhorn
Posts: 18
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Javaranchers:
Please try to predict the output of this question:
class A {
static A createA() {
return new A();
} // createA()
} // A

public class Tester {
public static void main(String[] parms) {
A aVar = null;
System.out.println(aVar.createA().hashCode());
} // main()
} // Tester
 
Ranch Hand
Posts: 787
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
It will print hashCode for an object of class A.
 
Greenhorn
Posts: 9
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
I think it should throw a NullPointerException as the aVar is null. The createA method is static so it can be invoked like A.createA().
Adnan
 
Ed B.
Greenhorn
Posts: 9
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Now that I tested the class, it does print out the hashcode. I am truly amazaed
 
Ranch Hand
Posts: 504
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Barkat's right: there's no problem with the code, you don't have to have an instance of a class to call its static(class) methods. e.g., Math class.
 
Can't .... do .... plaid .... So I did this tiny ad instead:
the value of filler advertising in 2021
https://coderanch.com/t/730886/filler-advertising
reply
    Bookmark Topic Watch Topic
  • New Topic