icedtea-web compatible with OpenJDK11

Wed Sep 5 18:45:12 UTC 2018

Dear Jiri,

Sorry for my late response, I was working hard on fixing IcedTea-Web 1.7
hanging problem (EDT) on OpenJDK11.
I reported this problem to awt-dev list and wrote a simple reproducer:
http://mail.openjdk.java.net/pipermail/awt-dev/2018-September/014264.html
http://mail.openjdk.java.net/pipermail/awt-dev/2018-September/014269.html

Today I managed fixing the AWT deadlock by using a workaround:
use a specific thread pool within the Main thread group (not JNLP's
AppContext) to relay the EDT invocations (invokeLater / invokeAndWait) as I
figured out that SplashScreen & DownloadIndicator dialogs were using the
JNLP AppContext
=> 2 concurrent AppContexts were used and 2 event dispatcher threads led to
deadlocks in AWT SequencedEvent processing (Window Gain / Lost focus).
With that workaround, all EDT actions from ITW are delivered to the Main
AppContext and it works well !
Of course, the application is still launched using its own separate
AppContext, so the bug is still critical if any ITW dialog (permission,
file check ?) can happen while the application is running.
My apps use allPermissions so I can not test. Do you have any example app ?

Moreover, I added the well known ThreadCheckingRepaintManager &
TracingEventQueue to detect and fix any EDT violation: it is OK, so I can
remove these classes.

Now it is time to clean up the code and submit patches !

Please see my comments in the text:

Le mer. 29 août 2018 à 16:37, Jiri Vanek <jvanek at redhat.com> a écrit :

> On 08/29/2018 03:37 PM, Laurent Bourgès wrote:
> > Hi,
> >
> > I am performing tests with icedtea-web-1.7 (cloned) + OpenJDK 11 EA 28
> (oracle build) to evaluate if
> > it can provide a suitable alternative to Oracle JDK on major platforms
> (win/mac/linux).
>
>
> Thank you *very* much for doing this!
>

Thank you all for all the good work on ITW. It made huge progresses in 10
years (fedora 11).
By the way, the control panel is great and it would be wonderful to open it
via 'javaws -viewer' (like O... jdk) or any other option.

Another issue I could do: JNLPClassLoader does many useless class/resouce
download queries if many child loaders are in action... let's see later.

> >
> > FYI I compiled icedtea-web-1.7 without plugin and modified the generated
> shell scripts (sh / bat) to
> Have you disabled both native and java parts of plugin, or only native?
>
> > successfully run my javaws applications on jdk11 (win/linux).
> > For example: http://jmmc.fr/~bourgesl/Aspro2/ <
> http://jmmc.fr/%7Ebourgesl/Aspro2/>
> Great! I'm really glad to hear this. when I was improving ITW launcher to
> survive jigsaw, usually
> ITW itself run well, but nearly all client applications were broken
> because of illegal access.
>

Yes our apps work almost on jdk11 (few third-party libs are causing issues).
I am very happy ITW works so well on jdk11 (linux), but jigsaw args are
missing in windows scripts, so I will rewrite them.

PS: how to set jigsaw CLI args in JNLP ? Did you try ? Does it change the
java command line ?

> Thank you very much for improving and verifying the sh/bats.
>

I tested linux shell scripts and only windows command line (derived from
linux CLI). It works also on mac (latest update) with ojdk11-28.

> I'm looking forward to see changes you mad!
>
> For future (1.8) ITW sh/bat launchers are being rewritten to rust, to
> avoid duplicated bat/sh code.
> The rust launchers are based 100% on current sh/bat, with improve in
> prebuild, downloadable packages
> for both windows and linux (currently linux is distribution only, but
> windows is downloadable)
>
> >
> > I had many times security dialogs hanging (XAWT lock issue), so I
> started diagnosing deadlocks
> > (jvisualvm) and fixed several EDT violations.
>
> This is exceptional. I'm aware of those locks, but never had solid
> reproducer nor time to debug it
> properly.
>

Thanks. It is definitely 'done' for javaws, maybe some issue remains in
control panel ...

> This patch will be heavily appreciated, and will be backported to 1.7 and
> will make candidate for
> another 1.7 release.
>

As I only worked on 1.7 code base, I could use webrev or just patches.
Do you prefer me to rebase on the bleeding edge repo ?

>
> > If I use -headless, -Xnofork or -Xtrustall, I have no hanging issue.
> > - Do you have any idea why separate AppContext are absolutely needed
> that maybe cause XAWT lock
> > deadlocks ?
>
> ITW and sandboxed application should be as separate as possible. Isnt
> Aseparate appcontext part of
> it? Maybe not. When I inherrited ITW, this was already there, so I keel in
> the habit.
>
> > - Running jdeps -jdkinternals (from jdk10) on the netx library reports
> lots of internal jdk usages,
> > do you plan fixing them ? I could help
>
> This should be fixed for future ITW. Any patch is welcomed. This is
> currently moreover one (busy)
> man show. So only small steps forward with development, a bit bigger with
> bugfixes,  but much
> smaller in cleanups.
>

As it is not blocking, I agree it can stay as it is. However some future
class removals in jdk could hurt.

>
> >
> > 1. Are you interested by some patch in netx code ?
>
> Definitely.
>
What form ? As webrev on cr.ojdk... ?

> > what is your contribution process (I am an openjdk commiter) ?
>
> ITW have different contribution process, as it is not hg.openjdk.net, but
> classpath.org.
> Looking to the quality of your research and fact that you are OpenJDK
> commiter, mean that you will
> post patch or two, I review them and will commit them on your behalf, and
> then I will nominate you
> for "classpath hacker" (poetic name:). Doing so, you will get push access
> to classpath repos.

> >
> > 2. In latest icedtea-web repo, the shell scripts were removed. So what
> is your plan for windows /
> > mac compatibility ?
>
> As written above - they are replaced by rust launchers. They are not
> removed, jsut moved, and marekd
> as deprecated if you built only them (configure switches). Still I intend
> to maintain them at least
> for itw 1.8 and maybe more further, as on Linux they are exceptionally
> useful. But in some time,
> they are likely to die, yes:(
>
> I have never run ITW on mac, nor have any feedback on its usage. Likely
> with oracle removing javaws,
> it can change. I have some machines rented from redhat to test ITW deeply
> on linux, and well, alsoa
> biton windows, but I'm far from being  expereinced window one. Still some
> effort is done to
> stabilise it. (many silently known issues for ITW on windows, but no more
> show stoppers). Main kudos
> for win port goes to Jacob, Alex and Michal and few students I had misused
> for it.
>

Great. I confirm my tests worked on mac too. Having an openjdk with
installer on mac would be awesome. My scientific users are mainly linux/mac
addicts.

>
> >
> > Finally IcedTea-Web seems a promising alternative on windows for OpenJDK
> 11, so I think openjdk
> > distributions should adopt it when OpenJDK 11 will be released.
> >
>
> Thank you for kind words, and an exceptional work you did on launchers,
> jdk11 testing and EDT
> violations.  I'm looking forward to see the patches, and I hope I will
> make theirs upstreaming as
> simple comfortable as possible to return the value.
>

Thank you for your very positive feedback, I will propose asap patches on:
1. Netx code (EDT)
2. shell scripts (linux then win)

Kindly regards from France (Grenoble),
Laurent
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