• 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
  • Liutauras Vilda
  • Tim Cooke
  • Jeanne Boyarsky
  • Paul Clapham
Sheriffs:
  • Devaka Cooray
  • Ron McLeod
  • paul wheaton
Saloon Keepers:
  • Tim Moores
  • Piet Souris
  • Tim Holloway
  • Stephan van Hulst
  • Carey Brown
Bartenders:
  • Al Hobbs
  • Frits Walraven
  • Scott Selikoff

Method with null as arg

 
Greenhorn
Posts: 12
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
In the below code, compiler error with message 'method is ambiguous'.

If I comment the method with StringBuffer as argument it compiles and gives "Object" as output. Can somebody explain why this happen ?

 
Ranch Hand
Posts: 1090
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Even if you comment the method that takes in a String argument it would work. The reason is that null is a valid argument for Object, String and StringBuffer. But the method with closest match is chosen over other methods for execution. Now when we have methods that accept Object type and String type of argument. String is more specific so the compiler knows that String method should be used. But when you have two or more completely different things(no where related in the class hierarchy) as the argumnet it is impossible for the compiler to determine which method should be called. Hence the error.
 
Ranch Hand
Posts: 377
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator

Originally posted by Anupam Sinha:
But when you have two or more completely different things(no where related in the class hierarchy) as the argumnet it is impossible for the compiler to determine which method should be called. Hence the error.



Even if the classes are related in the class hierarchy, it may be impossible for the compiler to decide which function should be called.

 
Shubha Kirani
Greenhorn
Posts: 12
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Thanks Anupam and Manfred for your replies. I'm understanding Java better now.
 
Of course, I found a very beautiful couch. Definitely. And this tiny ad:
the value of filler advertising in 2021
https://coderanch.com/t/730886/filler-advertising
reply
    Bookmark Topic Watch Topic
  • New Topic