A Java Syntax Quirk
This little trick is shamelessly stolen from Daniele Futtorovic’s post on comp.lang.java.programmer.
This is legal, compilable Java:
public class Oddity
{
public static void main(String[] args)
{
http://blog.uncommons.org
System.out.println("Why is the URL allowed above?");
}
}Why doesn’t the URL being in there upset the compiler? If you’re not sure why it’s valid, click “show” for a spoiler.
on August 24th, 2008 at 11:52 pm
A label, plus a comment!
Very funny, Thanks!
on August 25th, 2008 at 2:06 am
I’ve seen it somewhere before, isn’t it in the puzzler book?
on August 25th, 2008 at 2:35 am
Nice
on August 25th, 2008 at 5:19 am
Cool
Are you trying to get popular on digg? 
lol
on August 25th, 2008 at 8:12 am
Joshua Bloch and Neal Gafter wrote about this in their book: Java Puzzlers. I don’t really think it’s a quirk in the syntax, just a creative way to combine things.
on August 25th, 2008 at 12:37 pm
Casper/Ronald, you’re right, it’s puzzle 22. I have that book but I didn’t remember it when I saw Daniele’s post on CLJP.
on August 25th, 2008 at 1:32 pm
Very nice!
on August 25th, 2008 at 8:38 pm
Very nice… and funny at the same time…
I guess this is not just a Java quirk afterall… isn’t it valid for most C based languages? Appears so to be so.
on August 25th, 2008 at 10:18 pm
Nice one. Would be easier to spot with syntax highlighting!
on August 25th, 2008 at 10:29 pm
Patrick, you’re probably right. Single-line // comments aren’t strictly valid in C (they are a C++ innovation), but most compilers would probably accept them.
on August 26th, 2008 at 5:26 am
That’s really nice trick!
I was curious if all compilers out there does silently leave this.. It turns out that C# compiler issues a warning that “the label is not used”.
on August 26th, 2008 at 5:51 am
Is there a better way to read comp.lang.java.programmer. instead of going through google groups?
on August 26th, 2008 at 11:08 am
Un problema de sintaxis en Java…
Este texto ha sido "robado" sin vergüenza, del post A Java Syntax Quirk de Dan Dyer que a su…
on August 26th, 2008 at 11:44 am
Single-line comments are in C99 IIRC.
on August 26th, 2008 at 12:41 pm
[...] A Java Syntax Quirk [...]
on August 26th, 2008 at 12:54 pm
Subu, there are other web interfaces to USENET, though I can’t remember any at the moment.
Otherwise you’ll need a proper news reader. I just use the one built-in to Opera since that’s the browser that I use. You can use Thunderbird or Outlook Express or any of several others.
on August 26th, 2008 at 3:01 pm
[...] New Adventures in Software » A Java Syntax Quirk (tags: java puzzle syntax humor programming) [...]
on August 26th, 2008 at 7:56 pm
It’s valid in c#. I get a compile error that the label is not in use.
on August 26th, 2008 at 7:58 pm
[...] A Java Syntax Quirk [...]
on August 26th, 2008 at 10:16 pm
It’s also legal Javascript !
The syntax hilight really makes it look strange, though. Looks buggy, but isn’t
on August 26th, 2008 at 10:22 pm
Worked it out in seconds, but it was very interesting to see. Never thought of it myself.
Nice one
on August 26th, 2008 at 11:09 pm
// comments are valid in C99, the latest C revision.
on August 26th, 2008 at 11:11 pm
Hahaha.. great.. famous..
on August 27th, 2008 at 1:20 am
And if you ever use this in practice, you should be fired.
on August 27th, 2008 at 3:08 am
You can only do it once though. This doesn’t work
main(…) {
http://somesite.com
http://someothersite.com
}
on August 27th, 2008 at 3:11 am
That is cool. Thanks!
on August 27th, 2008 at 8:27 am
URL being there upset the compiler . Iit ain’t valid, unless you are referencing this label somwhere in your code
on August 27th, 2008 at 10:03 am
Oh, it’s old like the world
What about this ?
class String
{
public static void main(String args[])
{
String String = new String();
}
}
on August 27th, 2008 at 12:39 pm
[...] A Java Syntax Quirk [...]
on August 28th, 2008 at 7:59 am
Nice one. I would treat this as a trick(?) created by combining two java features.
Keep posting such tricks(?)
on September 8th, 2008 at 5:45 pm
[...] Idea originally from here. [...]
on September 9th, 2008 at 9:49 am
Am I missing something? What could you use this quirk for? Forgive me, I’m a frontend developer.
on September 9th, 2008 at 12:18 pm
Rauno, I don’t think you should use it anywhere
It’s just an interesting corner case.
on October 6th, 2008 at 12:23 am
[...] source: New Adventures in Software [...]