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Re: [jdt-dev] Incubating Java Language Features


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  feature when it is withdrawn later.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://bugs.openjdk.java.net/browse/JDK-8195734>". The conversation on the mailing list _starts here_ <http://mail.openjdk.java.net/pipermail/jdk-dev/2018-January/000515.html>. 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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