RFR 7118066: Warnings in java.util.concurrent package (original) (raw)
David Holmes david.holmes at oracle.com
Tue Dec 6 07:07:50 UTC 2011
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On 6/12/2011 12:14 PM, David Holmes wrote:
On 6/12/2011 11:45 AM, Rémi Forax wrote:
On 12/06/2011 02:12 AM, David Holmes wrote:
Is the reason for constructs like this:
HashEntry<K,V>[] tab = (HashEntry<K,V>[])new HashEntry[cap]; that we can't utilize diamond? Otherwise it would nicely reduce to: HashEntry<K,V>[] tab = new HashEntry<>[cap]; This should not compile because otherwise you can write This compiles fine: @SuppressWarnings("unchecked") public class TestGenerics<K,V> { static class HashEntry<K,V> { } public void m() { HashEntry<K,V>[] newTable = new HashEntry<>[1]; } } I don't know exactly what the type inference code does but I assumed it effectively converted the above to: HashEntry<K,V>[] newTable = (HashEntry<K,V>[]) new HashEntry[1]; and not to: HashEntry<K,V>[] newTable = new HashEntry<K,V>[1]; which of course does not compile.
Hmmm. Perhaps this is a compilation accident? I don't see anything in the spec that allows diamond to be used with array creation expressions.
David
David -----
HashEntry<String,String>[] tab = new HashEntry<>[12]; Object[] o = tab; o[1] = new HashEntry<Integer, Integer>(); The VM should reject the line above by throwing an ArrayStoreException but because of the erasure, it will not. So creating an array of parameterized type is only possible if you create a reifed type that inherits from an array of parameterized type. By example, this code is valid: enum Foo { foo } Enum[] enums = Foo.values(); Rémi
On 6/12/2011 1:36 AM, Chris Hegarty wrote: Cleanup warnings in the j.u.c. package. This is a sync up with the warning fixes in Doug's CVS. There are also a few style cleanups, import fixes, trivial local variable renaming, typos, etc. But nothing too surprising! http://cr.openjdk.java.net/~chegar/7118066/webrev.00/webrev/ -Chris. P.S. I have already reviewed this, and the contribution is of course from Doug.
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