Groups > comp.lang.java.programmer > #34745

Two surprises in for (:)

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From	Mike Amling <mamling@chaff.us>
Newsgroups	comp.lang.java.programmer
Subject	Two surprises in for (:)
Date	Fri, 1 Jul 2016 12:55:20 -0500
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I was surprised that the javac compiler accepted the following:

String[] foo={"a", "b"};
for (final String who : foo) {
}

because it seems strange to have a for loop's variable work when final. 
After all,

for (final int i=0; i<7; ++i) {
}

gets an error.

But for (final String who : foo) is more like an abbreviation of

for (final Iterator<String> iter=foo.iterator(); iter.hasNext(); ) {
   final String who=iter.next();
}

wherein it's not strange that who can be final.

My second surprise was that the compiler rejects

String[] foo={"a", "b"};
for (final Iterator<String> iter=foo.iterator(); iter.hasNext(); ) {
   final String who=iter.next();
}

apparently because arrays, unlike everything else accepted after the : 
in a for(:), do not actually implement the Iterable interface.

--Mike Amling
SSBzdXBwb3NlIGEgbG90IG9mIHlvdSBhcmUgbm90IHN1cnBpc2VkLg==

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Two surprises in for (:) Mike Amling <mamling@chaff.us> - 2016-07-01 12:55 -0500
  Re: Two surprises in for (:) Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-07-01 15:07 -0400
    Re: Two surprises in for (:) Daniel Pitts <usenet@coloraura.com> - 2016-07-01 15:08 -0700

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