JDK 9 RFR of JDK-8068948: Update java.base module to use new try-with-resources statement

[Ivan Gerasimov]

Hi!

A useful change!
Might it also make sense to allow anonymous variables in the 
try-with-resource statement?
So that something like `try (() -> System.out.println("closed")) {}` 
would work...

Would it make sense to also patch 
jdk/src/java.base/windows/classes/java/io/FileDescriptor.java in a 
similar manner, as it appears to contain the exactly same code?

Sincerely yours,
Ivan

On 14.01.2015 5:46, joe darcy wrote:
> Hello,
>
> Earlier in JDK 9, a language change was made so that if a resource for 
> a try-with-resources statement is already final or effectively final, 
> a new resource variable does *not* need to be declared to manage the 
> variable.
>
> The java.base module should take advantage of this language feature.
>
> I've run an experimental checker for such locations over the base 
> module and found one candidate where the new language feature can be 
> used; please review this patch for it:
>
> diff -r d873f6a7d16b 
> src/java.base/unix/classes/java/io/FileDescriptor.java
> --- a/src/java.base/unix/classes/java/io/FileDescriptor.java Tue Jan 
> 13 14:33:54 2015 -0800
> +++ b/src/java.base/unix/classes/java/io/FileDescriptor.java Tue Jan 
> 13 18:40:54 2015 -0800
> @@ -214,7 +214,7 @@
>          if (!closed) {
>              closed = true;
>              IOException ioe = null;
> -            try (Closeable c = releaser) {
> +            try (releaser) {
>                  if (otherParents != null) {
>                      for (Closeable referent : otherParents) {
>                          try {
>
> The build succeeds with this change and the java.io.FileDescriptor 
> regression tests pass.
>
> Thanks,
>
> -Joe
>
>