Java Answers Forum - Unboxing or toString()?

Articles |
News |
Weblogs |
Books |
Forums

Artima Forums | Articles | Weblogs | Java Answers | News

Sponsored Link •

Java Answers Forum
Unboxing or toString()?

1 reply on 1 page. Most recent reply: Oct 2, 2008 2:19 AM by Vincent O'Sullivan

Welcome Guest
Sign In

Back to Topic List

Reply to this Topic

Search Forum

Threaded View


Previous Topic		Next Topic

Flat View: This topic has 1 reply on 1 page

Vincent O'Sullivan

Posts: 724
Nickname: vincent
Registered: Nov, 2002

Unboxing or toString()?

Posted: Oct 1, 2008 11:02 PM

I've just been shown the following code from an Open University Java text book (M257 Unit 5 Page 21, to be precise):

		ArrayList<Character> holder = new ArrayList<Character>();
		holder.add('Z');
		System.out.println("The answer is " + holder.remove(0));

It is part of the text and not an exercise. It is cited as an example of unboxing but appears to be an example of toString() being invoked.

I don't think that unboxing is happening but I'm not certain, since each of the following three examples produce the same output:

		ArrayList<Character> holder = new ArrayList<Character>();
		holder.add('X');
		System.out.println("The answer is " + holder.remove(0));
		holder.add('Y');
		System.out.println("The answer is " + holder.remove(0).toString());
		System.out.println("The answer is " + 'Z');

Can anyone else say for certain what is happening here (i.e. that unboxing is or isn't happening in the initial example)?

Vincent O'Sullivan

Posts: 724
Nickname: vincent
Registered: Nov, 2002

Re: Unboxing or toString()?

Posted: Oct 2, 2008 2:19 AM

In answer to my own question. Putting the original code into the eclipse IDE yields a boxing warning but no unboxing warning. Substituting the println line with char c = holder.remove(0); does generate an unboxing warning. Therefore, I think that it's safe to assume that unboxing is not occurring in the original example.

Flat View: This topic has 1 reply on 1 page

Previous Topic

Next Topic


	Web Artima.com