up vote 3 down vote favorite

While I was trying something special in for loop I recognized that Java doesn't seem to like putting an anonymous array right as the source for a for-each-loop:

for (String crt : {"a","b","c"} ) {
    doSomething();
}

actually doesn't work while

String[] arr = {"a","b","c"};
for (String crt : arr ) {
    doSomething();
}

does.

Even casting the array to String[] doesn't help. When moving the cursor over the first version, eclipse tells me:

Type mismatch: cannot convert from String[] to String while meaning "crt".

Is this a bug?

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2  
Regarding "Is this a bug?": catb.org/~esr/faqs/smart-questions.html#id382249 – Joachim Sauer Mar 1 '10 at 20:32
I don't actually claim to have found a bug. I just ask whether it could be a bug. And it's strange that in one part this type of expression works and in another it doesn't. Not very consistent in my eyes. – Atmocreations Mar 1 '10 at 20:48
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4 Answers

up vote 15 down vote accepted

This will work:

for (String crt : new String[]{"a","b","c"} ) {
    doSomething();
}
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Accept: Shortest answer which provides a correct solution. Thanks! – Atmocreations Mar 1 '10 at 21:01
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up vote 7 down vote

The Java language provides the {"a","b","c"} form as a shortcut, but it is only possible during assignment. It's possible this is to avoid possible ambiguities during parsing, in some positions {} could be interpreted as a code block.

The right way to do it would be how noah suggests, with new String[]{"a","b","c"}.

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4  
Please note that that short form isn't allowed in all assignments. It is allowed only in initializations. – Joachim Sauer Mar 1 '10 at 20:54
@Joachim: interesting fact. This pretty much solves my question, thanks for pointing it out. @Tom Castle: +1 Good answer – Atmocreations Mar 1 '10 at 20:58
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up vote 1 down vote

Dunno, what about this? :) Pity there's no succinct version. Suppose you could use Groovy or Scala if you wanted anything like that :)

for (String s : Arrays.asList("a","b","c")) {
    hmm(s);
}
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sounds a bit like C# :P – Atmocreations Mar 1 '10 at 20:47
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up vote 1 down vote

You want

for (String crt : new String [] {"a","b","c"} ) {
    doSomething();
}

I use IntelliJ and it says put the message "expression expected" on the right-hand side of the colon in the for-loop, which seems more accurate.

I should add that IntelliJ also offers to add the "new String []" automagically for me.

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