Support Forums: Message List - An excellent Java puzzler http://www.theserverside.com Most recent forum messages en Jive Forums Silver 5.5.30 (www.jivesoftware.com) Tue, 21 May 2013 19:21:48 -0400 Re: Come on... http://www.theserverside.com/discussions/thread.tss?thread_id=53706 > Why is this particular one the ultimate? Two reasons:
> * It melted my brain when I hit it.

It melted YOUR brain? That surely makes this one "the ultimate"....]]> Wed, 25 Feb 2009 07:09:56 -0500 Wed, 25 Feb 2009 07:09:56 -0500 Wed, 25 Feb 2009 07:09:56 -0500 Feb 25, 2009 Jevgeni Kabanov 0 Perception is the issue here http://www.theserverside.com/discussions/thread.tss?thread_id=53706 It's not a common thing; I wouldn't have put main() in the m1 package, and if it's not local to M1 you won't see the behavior (it won't compile). But it's still an interesting corner case, and I think it's not obvious unless you've run...]]> Tue, 24 Feb 2009 19:13:33 -0500 Tue, 24 Feb 2009 19:13:33 -0500 Tue, 24 Feb 2009 19:13:33 -0500 Feb 24, 2009 Kenneth Beaton 0 Re: Come on... http://www.theserverside.com/discussions/thread.tss?thread_id=53706 Why is this particular one the ultimate? Two reasons: * It melted my brain when I hit it. It melted YOUR brain? That surely makes this one "the ultimate".]]> Tue, 24 Feb 2009 05:32:21 -0500 Tue, 24 Feb 2009 05:32:21 -0500 Tue, 24 Feb 2009 05:32:21 -0500 Feb 24, 2009 Hoogla Boogla 1 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706
I think what you don't understand is that for JVM class (or rather owner type as it can be interface) is always a part of the method name.
I've been arguing that C3.m doesn't have the same name...]]> Fri, 20 Feb 2009 18:32:01 -0500 Fri, 20 Feb 2009 18:32:01 -0500 Fri, 20 Feb 2009 18:32:01 -0500 Feb 20, 2009 Jevgeni Kabanov 0 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706
I think what you don't understand is that for JVM class (or rather owner type as it can be interface) is always a part of the method name.
I've been arguing that C3.m doesn't have the same name as C1.m....]]> Fri, 20 Feb 2009 14:58:03 -0500 Fri, 20 Feb 2009 14:58:03 -0500 Fri, 20 Feb 2009 14:58:03 -0500 Feb 20, 2009 James Watson 1 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706
I think what you don't understand is that for JVM class (or rather owner type as it can be interface) is always a part of the method name.
I've been arguing that C3.m doesn't have the same name as C1.m. You've...]]> Fri, 20 Feb 2009 14:32:53 -0500 Fri, 20 Feb 2009 14:32:53 -0500 Fri, 20 Feb 2009 14:32:53 -0500 Feb 20, 2009 Jevgeni Kabanov 2 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706 I think what you don't understand is that for JVM class (or rather owner type as it can be interface) is always a part of the method name.
...]]> Fri, 20 Feb 2009 10:34:45 -0500 Fri, 20 Feb 2009 10:34:45 -0500 Fri, 20 Feb 2009 10:34:45 -0500 Feb 20, 2009 James Watson 3 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706 C4 is definitely weird.

Note that C4.m does not know about super.m
...]]> Fri, 20 Feb 2009 10:15:54 -0500 Fri, 20 Feb 2009 10:15:54 -0500 Fri, 20 Feb 2009 10:15:54 -0500 Feb 20, 2009 James Watson 0 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706 So again, if your interpretation (as I understand it) were correct, c1.m() would resolve to C3.m(). The only way the spec can match the demonstrated behavior of this example is if the method C3.m() is not considered to have the same name...]]> Fri, 20 Feb 2009 04:59:31 -0500 Fri, 20 Feb 2009 04:59:31 -0500 Fri, 20 Feb 2009 04:59:31 -0500 Feb 20, 2009 Jevgeni Kabanov 4 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706
I don't know of any other language that allows shadowing for virtual methods or specially the weird skipping of classes in hierarchy.


Someone on your blog suggest similar things can be shown with C++ but I...]]> Fri, 20 Feb 2009 04:43:03 -0500 Fri, 20 Feb 2009 04:43:03 -0500 Fri, 20 Feb 2009 04:43:03 -0500 Feb 20, 2009 jido 1 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706
In order for this to be an accurate description of how Java works, C in the above has to be the runtime type of the object, not the type of the reference.

This confused me too at first. The important part is what...]]> Thu, 19 Feb 2009 11:53:11 -0500 Thu, 19 Feb 2009 11:53:11 -0500 Thu, 19 Feb 2009 11:53:11 -0500 Feb 19, 2009 James Watson 5 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706 In order for this to be an accurate description of how Java works, C in the above has to be the runtime type of the object, not the type of the reference.
...]]> Thu, 19 Feb 2009 11:36:50 -0500 Thu, 19 Feb 2009 11:36:50 -0500 Thu, 19 Feb 2009 11:36:50 -0500 Feb 19, 2009 Jevgeni Kabanov 6 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706 Let's start with the less fun part:
What I don't understand about your explanation is how I would get that output if all the JVM were doing was skipping methods that are not accessible. In this case, all versions of m() are...]]> Thu, 19 Feb 2009 10:32:35 -0500 Thu, 19 Feb 2009 10:32:35 -0500 Thu, 19 Feb 2009 10:32:35 -0500 Feb 19, 2009 James Watson 7 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706 Wed, 18 Feb 2009 18:23:30 -0500 Wed, 18 Feb 2009 18:23:30 -0500 Wed, 18 Feb 2009 18:23:30 -0500 Feb 18, 2009 Jevgeni Kabanov 0 Re: An excellent Java puzzler http://www.theserverside.com/discussions/thread.tss?thread_id=53706 This probably explains why you see this as so surprising and I do not. The VM spec and the JLS are slightly at odds here (the JVM being more lenient.) The compiler says that code isn't valid but the JVM links the calls to C1. I'm much more...]]> Wed, 18 Feb 2009 18:21:52 -0500 Wed, 18 Feb 2009 18:21:52 -0500 Wed, 18 Feb 2009 18:21:52 -0500 Feb 18, 2009 Jevgeni Kabanov 0