Re: RFR: 8272756: Remove unnecessary explicit initialization of volatile variables in java.desktop
On Mon, 23 Aug 2021 17:57:52 GMT, Sergey Bylokhov wrote: >> Maybe it's kind of a protection from a race. Yet it's possible either way: >> another thread could see `essentialTags == null` before this one initialises >> the field. > > I think we can drop it completely. Agree. - PR: https://git.openjdk.java.net/jdk/pull/5197
Re: RFR: 8272756: Remove unnecessary explicit initialization of volatile variables in java.desktop
On Mon, 23 Aug 2021 13:08:02 GMT, Alexey Ivanov wrote: >> Looks like there's no purpose, `tags` is not used after assignment > > Maybe it's kind of a protection from a race. Yet it's possible either way: > another thread could see `essentialTags == null` before this one initialises > the field. I think we can drop it completely. - PR: https://git.openjdk.java.net/jdk/pull/5197
Re: RFR: 8272756: Remove unnecessary explicit initialization of volatile variables in java.desktop
On Mon, 23 Aug 2021 06:35:34 GMT, Сергей Цыпанов
wrote:
>> src/java.desktop/share/classes/com/sun/imageio/plugins/tiff/TIFFIFD.java
>> line 64:
>>
>>> 62: Set tags = essentialTags;
>>> 63: if (tags == null) {
>>> 64: essentialTags = Set.of(
>>
>> What is the purpose of the local tags here?
>
> Looks like there's no purpose, `tags` is not used after assignment
Maybe it's kind of a protection from a race. Yet it's possible either way:
another thread could see `essentialTags == null` before this one initialises
the field.
-
PR: https://git.openjdk.java.net/jdk/pull/5197
Re: RFR: 8272756: Remove unnecessary explicit initialization of volatile variables in java.desktop
On Fri, 20 Aug 2021 21:26:41 GMT, Sergey Bylokhov wrote:
>> This is a continuation of
>>
>> - https://bugs.openjdk.java.net/browse/JDK-6736490
>> - https://bugs.openjdk.java.net/browse/JDK-8035284
>> - https://bugs.openjdk.java.net/browse/JDK-8145680
>> - https://bugs.openjdk.java.net/browse/JDK-8251548
>>
>> As mentioned in JDK-6736490:
>>
>> _An explicit initialization of a volatile class instance variable, such as
>> private volatile Object = null; or private volatile int scale = 0; is
>> unnecessary since the Java spec automatically initializes objects to null
>> and primitive type short, int, long, float and double to 0 and boolean to
>> false. Explicit initialization of volatile variable to a value the same as
>> the default implicit initialized value results in an unnecessary store and
>> membar operation._
>
> src/java.desktop/share/classes/com/sun/imageio/plugins/tiff/TIFFIFD.java line
> 64:
>
>> 62: Set tags = essentialTags;
>> 63: if (tags == null) {
>> 64: essentialTags = Set.of(
>
> What is the purpose of the local tags here?
Looks like there's no purpose, `tags` is not used after assignment
-
PR: https://git.openjdk.java.net/jdk/pull/5197
Re: RFR: 8272756: Remove unnecessary explicit initialization of volatile variables in java.desktop
On Fri, 20 Aug 2021 09:41:15 GMT, Сергей Цыпанов
wrote:
> This is a continuation of
>
> - https://bugs.openjdk.java.net/browse/JDK-6736490
> - https://bugs.openjdk.java.net/browse/JDK-8035284
> - https://bugs.openjdk.java.net/browse/JDK-8145680
> - https://bugs.openjdk.java.net/browse/JDK-8251548
>
> As mentioned in JDK-6736490:
>
> _An explicit initialization of a volatile class instance variable, such as
> private volatile Object = null; or private volatile int scale = 0; is
> unnecessary since the Java spec automatically initializes objects to null and
> primitive type short, int, long, float and double to 0 and boolean to false.
> Explicit initialization of volatile variable to a value the same as the
> default implicit initialized value results in an unnecessary store and membar
> operation._
src/java.desktop/share/classes/com/sun/imageio/plugins/tiff/TIFFIFD.java line
64:
> 62: Set tags = essentialTags;
> 63: if (tags == null) {
> 64: essentialTags = Set.of(
What is the purpose of the local tags here?
-
PR: https://git.openjdk.java.net/jdk/pull/5197
RFR: 8272756: Remove unnecessary explicit initialization of volatile variables in java.desktop
This is a continuation of - https://bugs.openjdk.java.net/browse/JDK-6736490 - https://bugs.openjdk.java.net/browse/JDK-8035284 - https://bugs.openjdk.java.net/browse/JDK-8145680 - https://bugs.openjdk.java.net/browse/JDK-8251548 As mentioned in JDK-6736490: _An explicit initialization of a volatile class instance variable, such as private volatile Object = null; or private volatile int scale = 0; is unnecessary since the Java spec automatically initializes objects to null and primitive type short, int, long, float and double to 0 and boolean to false. Explicit initialization of volatile variable to a value the same as the default implicit initialized value results in an unnecessary store and membar operation._ - Commit messages: - 8272756: Remove unnecessary explicit initialization of volatile fields in java.desktop Changes: https://git.openjdk.java.net/jdk/pull/5197/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk=5197=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8272756 Stats: 50 lines in 25 files changed: 0 ins; 0 del; 50 mod Patch: https://git.openjdk.java.net/jdk/pull/5197.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/5197/head:pull/5197 PR: https://git.openjdk.java.net/jdk/pull/5197
