Date: Thu, 3 Jun 2004 12:08:10 -0400 From: Daniel Fisher <daniel.fisher@vt.edu> To: java@freebsd.org Subject: Re: possible threading problem Message-ID: <20040603120810.096a1975@psych.iad.vt.edu> In-Reply-To: <opr8zfpxqaydasmi@outgoing.local> References: <20040601154601.0869f5b4@psych.iad.vt.edu> <40BD7C06.5050205@noc.ntua.gr> <20040602095245.48cb3c44@psych.iad.vt.edu> <opr8zfpxqaydasmi@outgoing.local>
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On Wed, 02 Jun 2004 21:42:59 +0200
Ronald Klop <ronald@cs.vu.nl> wrote:
> On Wed, 2 Jun 2004 09:52:45 -0400, Daniel Fisher <daniel.fisher@vt.edu>
> wrote:
>
> > On Wed, 02 Jun 2004 10:04:38 +0300
> > Panagiotis Astithas <past@noc.ntua.gr> wrote:
> >
> >> Daniel Fisher wrote:
> >> > I'm experiencing a weird threading problem with jdk-1.4.2p6_3 that I
> >> don't
> >> > see on Linux.
> >> > It looks like the BSD JDK is not honoring sychronize statements.
> >> > Has anyone seen this before?
> >> > If not, who should I send sample code to?
> >>
> >> Um, the list?
> >> --
> >> Panagiotis Astithas
> >
> > Alrighty then....
> > attached is a tarball with the sample classes in it.
> > Untar and cd into the directory.
> > Execute: java -jar prop.jar
> > These classes monitor the main.properties file and echo the changes to
> > stdout.
> > Edit main.properties while the java job is running.
> > FreeBSD JVM throws an InterruptedIOException, Linux JVM does not throw an
> > exception.
>
> Add debugging like, so you can make sure synchronized is (not) working.
> synchronized (a) {
> System.out.println("In a 1");
> ...
> System.out.println("Out a 1");
> }
>
> If I recompile your program I get other results after modifying the
> properties file.
> java.lang.NoClassDefFoundError: prop/PropEvent
> at prop.PropSingleton.removeProperties(PropSingleton.java:74)
> at prop.PropMonitor.run(PropMonitor.java:71)
> at java.lang.Thread.run(Thread.java:534)
>
> PropMonitor interrupts itself. Why? it's useless.
> By the way if you don't do this your program works.
>
> Offtopic:
> In PropMonitor you catch Exception. So you will mis all other possible
> error messages from java.
> If this is not just a test class I would rewrite it.
> Why this:
> try {
> throw Exception();
> } catch (Exception) {
> break;
> }
>
> You can also just do break in stead of the exception.
> And you can remove all the interrupt/interrupted calls. Only keep the
> boolean run.
> And even nicer than the break is setting run = false to end the while.
>
> But only removing the stopMonitor call from PropMonitor.run() will also
> make it work. :-)
>
> Ronald.
>
I think you've missed the point.
The question is, why does the BSD JVM behave differently and does it need
fixing?
--
Daniel Fisher
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