• 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

core java programming doubts

 
Ranch Hand
Posts: 92
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Please clarify some doubts:

1. When I execute this class




I get the output : In add in class A
In add in class A

Please explain what is happening here.Is it overloading or overriding.


2.I have an ArrayList



Can I make the list readonly ,no other values must be added to the List.

 
Ranch Hand
Posts: 633
Android Eclipse IDE Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Please use code tags, without code tags it is difficult to read the program.
 
Pramod P Deore
Ranch Hand
Posts: 633
Android Eclipse IDE Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator

Is it overloading or overriding



Because overloaded methods must differ in the type and/or number of their parameters. Therefore it is method overloading.
 
p hasini
Ranch Hand
Posts: 92
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
How do I set the code tags
 
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

Can I make the list readonly ,no other values must be added to the List.


The Collections class has some utility methods to wrap collections and make them unmodifiable. For example, Collections#unmodifiableList.
 
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

p hasini wrote:How do I set the code tags


UseCodeTags
 
Pramod P Deore
Ranch Hand
Posts: 633
Android Eclipse IDE Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
This time someone (bartender) set it for you. But please use code tags in future. using code button before posting your post, or click on edit button after posting your post and set them
 
Java Cowboy
Posts: 16084
88
Android Scala IntelliJ IDE Spring Java
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
1. The add() method in class B does not override the add() method in class A, because the argument types are not the same. X and Y are subclasses of E and S, but they are not the same. Because of this, the method to call is determined at compile time, by looking at the type of the variable a, which is A (there is no dynamic dispatch, as you would have when there was overriding).

2. You can effectively make the ArrayList read-only by wrapping it like this:

 
p hasini
Ranch Hand
Posts: 92
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Thank you
 
Marshal
Posts: 79177
377
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
When it says unmodifiableList, that means the List returned cannot be modified, but it remains a copy of the original List. Any changes to the original List are reflected in the unmodifiable copy, so I think it might have been better to call the method readOnlyList.
 
get schwifty. tiny ad:
a bit of art, as a gift, the permaculture playing cards
https://gardener-gift.com
reply
    Bookmark Topic Watch Topic
  • New Topic