Re: [jnc-users] AttachCurrentThread

[Marco T. <mt...@gm...>]

Hey Marko

Marko Mocnik wrote:
> Hi!
> 
> I am trying to compile a little GUI app with a system tray icon (systray4j).
> The app worked fine with sun java, but not to require a JRE is one of  
> my top goals.

Windows? Linux?
AWT? Swing? SWT? You'll be best off with SWT.

> I used the latest release 1.1.1 with gcc-122233-win
> Everything compiled but I ran into two problems:
> 
> First:
> Systray4j uses a native thread, which causes trouble.
> These lines:
> ---------------------------------------------------------------
> JDK1_1AttachArgs thread_args;
> s_pVm->AttachCurrentThread( ( void** ) &s_pEnv, &thread_args );
> ---------------------------------------------------------------
> leave me with a NULL Environment.
> 
> I did a quick search in the GNU Bugzilla and couldn’t find anything on it.

Directly, I have no idea what could be the reason for this. I think you 
should ask this on the GCJ users mailinglist.

> Second:
> Without systray, the app launches.
> But after a while, when I click some buttons or tabs, the GUI Thread  
> freezes and the app is no longer responding to anything.
> That freezing can’t be fixed to any action, sometimes it happens even  
> before the JFrame is fully visible.

There's probably a thread race respectively wrong synchronized code. The 
mingw port of GCJ has a bug that sometimes wait() can be signaled by a 
preceding signal().
Now please note the Sun Javadoc of wait:

As in the one argument version, interrupts and spurious wakeups are 
possible, and this method should always be used in a loop:

      synchronized (obj) {
          while (<condition does not hold>)
              obj.wait();
          ... // Perform action appropriate to condition
      }

I guess now that your code doesn't loop for the wait and while - luckily 
- it never runs into problems with a Sun JRE, GCJs additional bug will 
expose the bug in your code.


> I would really appreciate any help here.

I assume you're programming AWT/Swing on Windows. If you want to be rid 
of any problems, use SWT. It has built-in support for system tray icons 
and SWT is fully supported with JNC/GCJ.


Hope that helps
Marco


> Thanks and bye,
> 
> Marko
> 
> 
> -------------------------------------------------------------------------
> This SF.net email is sponsored by: Splunk Inc.
> Still grepping through log files to find problems?  Stop.
> Now Search log events and configuration files using AJAX and a browser.
> Download your FREE copy of Splunk now >>  http://get.splunk.com/
> _______________________________________________
> javaCompiler-users mailing list
> jav...@li...
> https://lists.sourceforge.net/lists/listinfo/javacompiler-users