<div dir="ltr"><div dir="ltr"><div class="gmail_default" style="font-family:trebuchet ms,sans-serif"><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jun 10, 2020 at 5:09 PM David Lloyd <<a href="mailto:david.lloyd@redhat.com">david.lloyd@redhat.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Wed, Jun 10, 2020 at 4:41 PM Brian Stansberry<br>
<<a href="mailto:brian.stansberry@redhat.com" target="_blank">brian.stansberry@redhat.com</a>> wrote:<br>
><br>
> Thanks for this thread, Paul.<br>
><br>
> On Wed, Jun 10, 2020 at 3:31 PM Paul Ferraro <<a href="mailto:paul.ferraro@redhat.com" target="_blank">paul.ferraro@redhat.com</a>> wrote:<br>
>><br>
>> In version 30 of jboss-parent-pom, David Lloyd added the ability to<br>
>> easily produce multi-release jars [1]. While several components<br>
>> consumed by WildFly currently produce multi-release jars (e.g.<br>
>> wildfly-common, Undertow, Infinispan, etc.), as far as I am aware,<br>
>> none of the modules in WildFly (or wf-core) do this.<br>
>><br>
>> I recently created a pull request to WildFly [2] that ports a<br>
>> collection class from Undertow [3], which, when built using Java 9+,<br>
>> results in faster expiration scheduling for persistent HttpSessions<br>
>> and local @Stateful EJBs. While the changes introduced in this PR are<br>
>> still compatible with JDK 8 [4], this optimization will not be<br>
>> available to users unless they build wildfly using JDK 9+ in order to<br>
>> produce the requisite multi-release jar for the<br>
>> wildfly-clustering-ee-cache module.<br>
>><br>
>> What do people think about this?<br>
>><br>
>> Is there any reason why we should *not* compile using JDK 11 when<br>
>> building releases (while still maintaining Java 8 source<br>
>> compatibility, of course)?<br>
><br>
><br>
> One issue I can think of is CI. We'd probably need to alter jobs to build with JDK 11 and then test with JDK 8. I think our integration testsuite runs for JDK 8 should be running a server built the way a released server is built.<br>
><br>
> The tests in the subsystems wouldn't run with JDK 8 unless we had separate jobs just for that purpose (which is no big deal.)<br>
<br>
By adding an empty file named `build-test-java8` to each module<br>
directory, and by having JDK 8 present in the test environment (in<br>
addition to JDK 11), the modules will be tested with both JDK 8 and<br>
JDK 11 while being built. It is necessary to pass in a property to<br>
Maven called `java8.home` pointing to the location of the JDK 8<br>
installation to make this work. Doing so is much faster (overall, in<br>
CPU-time) than having two completely separate CI jobs, one for 8 and<br>
one for 11, because even though the tests would run sequentially, the<br>
majority of the setup and build will be done only one time instead of<br>
twice. It would somewhat increase wallclock time due to the<br>
sequential nature of testing with 8 and again with 11.<br></blockquote><div><br></div><div class="gmail_default" style="font-family:"trebuchet ms",sans-serif">Thanks, David.</div><div class="gmail_default" style="font-family:"trebuchet ms",sans-serif"></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br>
> To be fair, our JDK 11 CI jobs are building with JDK 11 and then testing that, and our releases are built with JDK 8. So the existence of a mismatch is not new. My impression though is JDK 8 remains dominant, so shifting the mismatch to the JDK 8 side is a concern.<br>
><br>
> This isn't a showstopper kind of thing for me, it's just something to think about and make a conscious plan.<br>
<br>
-- <br>
- DML<br>
<br>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr">Brian Stansberry<div>Manager, Senior Principal Software Engineer</div><div>Red Hat</div></div></div></div>