Re: [jdt-dev] Incubating Java Language Features

["Daniel Megert" <daniel_megert@xxxxxxxxxx>]

As per https://bugs.openjdk.java.net/browse/JDK-8195734the umbrella JSR for a release will enumerate which incubation JEPs have
to be implemented. There's nothing optional where JDT could decide what
incubating features to implement for a specific release.

The known problem
for JDT will probably be the usual restriction in the license (I just assuming
here) where Eclipse (and all others) are not allowed to ship the ongoing
implementation with an Eclipse release.

However, a much
bigger problem I envision is that there are already many JEPs at the door
that might soon be brought forward for incubation and which JDT did not
look at at all because we could always only focus on what was marked for
a release. Given that incubation features must also be implemented to comply
with the JSR specification, JDT might no longer be able to deliver Eclipse
Java X support at the same time as the GA of a Java X.

Dani



From:
       Mike
Milinkovich <mike.milinkovich@xxxxxxxxxxxxxxxxxxxxxx>
To:
       jdt-dev@xxxxxxxxxxx
Date:
       30.01.2018
14:21
Subject:
       Re:
[jdt-dev] Incubating Java Language Features
Sent
by:        jdt-dev-bounces@xxxxxxxxxxx

---

Perhaps I was wrong, but I thought that you relied upon the JSRs to 
drive what gets implemented in ecj. I thought that one of the big 
changes here was that you will now have to closely follow the OpenJDK 
discussions. Is there an IP issue here that needs to be discussed?


On 2018-01-30 7:45 AM, Stephan Herrmann wrote:
> Jay,
>
> not sure this answers your concerns, but the email thread on jdk-dev
> makes a strong point in saying that incubating features are not
> experimental. I read this as: the process for an incubating feature
> is essentially the same as for a permanent feature. The main changes
> for us would thus be:
> - we need to implement the switch that can turn of a certain feature
> - we must be prepared to pull the plug and completely remove a
>   feature when it is withdrawn later.
> (the former is common practice, that latter may well be tricky)
>
> IOW, "evolving simultaneously" doesn't seem to imply that
we should
> implement weekly updates of a feature. When it's included in a release
> it's supposed to have production quality. Only when a feature
> re-incubates, there's a window of opportunity for changing its spec
> within the next 6 months time frame.
>
> Do you interpret the information differently?
> Stephan
>
> On 30.01.2018 12:55, Jayaprakash Arthanareeswaran wrote:
>> Thanks Mike.
>>
>> I believe, some of these were already happening already as part
of 
>> the openjdk development process. But just as in the past, the
>> "impermanent" nature of these feature is definitely
a concern for us, 
>> the JDT team. What makes it a bigger concern is this, (based on
my 
>> understanding, of course):
>>
>> The compilers and runtimes should support these incubating features,
>> although they are turned off by default. This basically means
every 
>> compiler implementation should evolve simultaneously with respect
to 
>> the incubating features. But at the same time, not all of them
are 
>> certain to be a permanent feature.
>>
>> Even if the above is not true, it is going to be a challenge to
>> decide our own plan based on the direction the incubating feature
is 
>> going to take. Are we to build these features even as the discussions
>> happen or are we to wait for these to become permanent and start
on 
>> our implementation.
>>
>> Either way, it's going to be quite a challenge!
>>
>> Regards,
>> Jay
>>
>>
>>
>>
>>
>>
>> From: Mike Milinkovich <mike.milinkovich@xxxxxxxxxxxxxxxxxxxxxx>
>> To: jdt-dev@xxxxxxxxxxx
>> Cc: eclipse-pmc@xxxxxxxxxxx, Wayne Beaton 
>> <wayne.beaton@xxxxxxxxxxxxxxxxxxxxxx>
>> Date: 01/30/2018 04:42 PM
>> Subject: [jdt-dev] Incubating Java Language Features
>> Sent by: jdt-dev-bounces@xxxxxxxxxxx
>> ------------------------------------------------------------------------------------------------------------------------------------
>>
>>
>>
>>
>> All,
>>
>> Just in case you've missed it, I would like to draw your attention
to 
>> a recent proposal on the jdk-dev list entitled "_Incubating
Language 
>> and VM Features_ <https://urldefense.proofpoint.com/v2/url?u=https-3A__bugs.openjdk.java.net_browse_JDK-2D8195734&d=DwIGaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=1UITCR5rxUZHSFczvfaNFK4ymEbEiccRX7VKchpqz0Y&m=PoHnsLGDwD9AiJodjpFFDGD5QqcvTG97DFFZeJVZSZ4&s=TE0zGOYvXay7RDLkv7izRAAG8BC2bMx0oe2QYj294og&e=>".
>> The conversation on the mailing list _starts here_ 
>> <https://urldefense.proofpoint.com/v2/url?u=http-3A__mail.openjdk.java.net_pipermail_jdk-2Ddev_2018-2DJanuary_000515.html&d=DwIGaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=1UITCR5rxUZHSFczvfaNFK4ymEbEiccRX7VKchpqz0Y&m=PoHnsLGDwD9AiJodjpFFDGD5QqcvTG97DFFZeJVZSZ4&s=NpAjz9n2pjG9QhCbhMYkPRP30N36YKtzeLQPWUe12mY&e=>.
>> At its core, I *think* this means that staying abreast of new
>> language features will require engaging with OpenJDK rather than
JSRs 
>> hosted at the JCP.
>>
>> Important quote:
>>
>> The Umbrella JSR for the Java SE $N Platform enumerates the 
>> incubating language and VM features in the platform. The desire
for 
>> feedback and the expectation of quality means that these features
are 
>> not "optional"; they must all be supported in full by
every 
>> implementation of the Umbrella JSR. They are specified in appendices
>> of the Java SE $N Editions of the Java Language Specification
(JLS) 
>> and the Java Virtual Machine Specification (JVMS). The Java 
>> Compatibility Kit for Java SE $N checks conformance of an 
>> implementation's incubating features to the appropriate appendix.
>>
>> If you have any thoughts or concerns about how this may impact
ecj or 
>> JDT in general, please comment on the jdk-dev mailing list. If
there 
>> is anything I or the EMO can assist with, please let me know.
>>
>> Thanks. 

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