Evgueni,
On 10/11/06, Nikolay Kuznetsov <[EMAIL PROTECTED]> wrote:
> I have a quick note about detaching current thread. I've filled
> HARMONY-1816 issue about counting non daemon threads. And concerning
> DetachCurrentThread we should either detach it
I don't understand your concern.... what should we detach? Could you
give an example or test case?
HARMONY-1816 contains such a test case, it hangs because child thread
works a bit longer than main method. In this case main method exits,
but the main thread enters
wait for all non daemon treads method. It checks that non daemon count
1, 1 stands for itself and enters while cycle with condition that
non-daemon threads should be equal to zero, while the main thread also
non-daemon.
> or rewrite
> wait_for_all_nondaemon threads to take into account the fact that main
> thread is also non daemon.
First of all we should not do any assumption regarding main thread. It
doesn't differ from any other non daemon thread. It may die long
before last non daemon thread dies. DestroyJavaVM may be called by any
thread....even unattached...
I agree, but the thread which counts non-daemon threads should take
into account that it itself may also daemon or non-daemon and count
other threads till 1 or 0 or detach(or countdown non-daemon threads)
itself before waiting.
Nik.
Thanks Evgueni
>
> Nik.
> On 10/11/06, Evgueni Brevnov <[EMAIL PROTECTED]> wrote:
> > Oliver,
> >
> > I created https://issues.apache.org/jira/browse/HARMONY-1819 with
> > suggested fix. Please, look at and update it if DetachCurrentThread is
> > required before DestroyJavaVM for some reason.
> >
> > Thanks
> > Evgueni
> >
> > On 9/22/06, Evgueni Brevnov <[EMAIL PROTECTED]> wrote:
> > > On 9/22/06, Oliver Deakin <[EMAIL PROTECTED]> wrote:
> > > > Tim Ellison wrote:
> > > > > Still, it seems strange that you should have to call
DetachCurrentThread
> > > > > explicitly to get this behavior. I would have expected that
> > > > > DestroyJavaVM alone would cause the uncaught exception handler to
fire.
> > > > > Not all apps that embed the VM will know to make this work-around.
> > > > >
> > > >
> > > > Yes, that surprised me too. The bug suggests that the launcher is at
> > > > fault for calling
> > > > ExceptionDescribe() instead of DetachCurrentThread(). However I would
have
> > > > thought that this was not necessary in the case where an exception
> > > > handler has
> > > > been registered, and that the handler would be called during
> > > > DestroyJavaVM()'s
> > > > execution.
> > > >
> > > > Perhaps this is something that could be "fixed" in DRLVM? So if
> > > > DetachCurrentThread() is called, it runs any registered exception
> > > > handlers for that
> > > > thread as usual. However, if DestroyJavaVM is called, it makes sure
that all
> > > > exception handlers are run for every thread.
> > > >
> > >
> > > Sure, I checked both cases work fine on my implementation of
> > > InvocationAPI for DRLVM (with DetachCurrentThread and without it). So
> > > the launcher can choose either to detach the main thread or not...
> > >
> > > Thanks
> > > Evgueni
> > >
> > > > Regards,
> > > > Oliver
> > > >
> > > > > Regards,
> > > > > Tim
> > > > >
> > > > > Oliver Deakin wrote:
> > > > >
> > > > >> Evgueni Brevnov wrote:
> > > > >>
> > > > >>> Oliver,
> > > > >>>
> > > > >>> Yes, I got the same result on RI when starting VM by your simple
> > > > >>> launcher. Assume it is OK not to print an error message and stacke
> > > > >>> trace of an unhandled exception in JavaDestroyVM(). How about
calling
> > > > >>> uncaught exception handler? According to the spec it must be called
if
> > > > >>> terminating thread has an exception. The test shows that the handler
> > > > >>> is not called when VM is created by our launcher. But if VM is
> > > > >>> created by RI's launcher then everything works fine and the handler
is
> > > > >>> executed. This means that RI's launcher somehow deals with it (not
VM
> > > > >>> itself). It seems for me as a bug in RI. Do you think so?
> > > > >>>
> > > > >> Hi Evgueni,
> > > > >>
> > > > >> I see the same thing - if I run your second Test class (the
> > > > >> UncaughtExceptionHandler
> > > > >> test) with my simple launcher on the RI and J9 I do not see any
output.
> > > > >> i.e. the MyHandler.uncaughtException() method is never called.
> > > > >>
> > > > >> Having a Google around I found a link to a Sun bug registered for
this [1].
> > > > >> All our launcher needs to do is call DetachCurrentThread() on the
main
> > > > >> thread before DestroyJavaVM(), and the UncaughtExceptionHandler will
> > > > >> be called as expected. (This bug only occurs with exception handlers
> > > > >> registered to the main thread - I verified this with [2] which has
its
> > > > >> non-main
> > > > >> thread's exception handler called correctly)
> > > > >>
> > > > >> So if you add the line:
> > > > >> (*jvm)->DetachCurrentThread(jvm);
> > > > >> to my simple launcher just before the DestroyJavaVM() call, you will
see
> > > > >> that the MyHandler.uncaughtException() is called for the main
thread, and
> > > > >> the test works as expected.
> > > > >>
> > > > >> This looks like it needs to be added to our launcher - do you agree?
> > > > >>
> > > > >> What is even more interesting is that if I run your more simple Test
class
> > > > >> (the one that just does 'throw new Error("my");'), with the
> > > > >> DetachCurrentThread()
> > > > >> call added to the simple launcher I get a stack trace printed on
both RI
> > > > >> and J9!
> > > > >> Again it appears that this is only a problem with the main thread (if
> > > > >> you alter
> > > > >> [2] before so that the handler is not registered, you get the
expected
> > > > >> stack trace).
> > > > >> So it seems that adding DetachCurrentThread to the launcher fixes
both
> > > > >> problems!
> > > > >>
> > > > >> Regards,
> > > > >> Oliver
> > > > >>
> > > > >> [1] http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4992454
> > > > >> [2]
> > > > >> public class Test {
> > > > >> static class MyHandler implements Thread.UncaughtExceptionHandler
{
> > > > >> public void uncaughtException(Thread t, Throwable e) {
> > > > >> System.out.println("My Handler Called!!!");
> > > > >> }
> > > > >> }
> > > > >>
> > > > >> static class MyRunnable implements Runnable {
> > > > >> public void run() {
> > > > >> Thread.currentThread().setUncaughtExceptionHandler(new
> > > > >> MyHandler());
> > > > >> throw new Error("my");
> > > > >> }
> > > > >> }
> > > > >>
> > > > >> public static void main(String [] args) {
> > > > >> Thread t = new Thread(new MyRunnable());
> > > > >> t.start();
> > > > >> try {
> > > > >> t.join();
> > > > >> } catch (InterruptedException e) {
> > > > >> System.out.println("Interrupted!");
> > > > >> }
> > > > >> }
> > > > >> }
> > > > >>
> > > > >>
> > > > >>> Evgueni
> > > > >>>
> > > > >>> On 9/21/06, Oliver Deakin <[EMAIL PROTECTED]> wrote:
> > > > >>>
> > > > >>>> Hi Evgueni,
> > > > >>>>
> > > > >>>> I wrote a simple launcher [1] that does the following:
> > > > >>>> 1) Calls CreateJavaVM
> > > > >>>> 2) Runs the main method of your Test class below
> > > > >>>> 3) Calls DestroyJavaVM
> > > > >>>>
> > > > >>>> Note that it does *not* call env->ExceptionDescribe() before
destroying
> > > > >>>> the VM.
> > > > >>>> I tested this launcher against the RI and J9 and found that no
stack
> > > > >>>> trace or
> > > > >>>> error details are printed.
> > > > >>>> So I would say that it is standard behaviour for the VM not to
output
> > > > >>>> any
> > > > >>>> information about uncaught exceptions when shutting down, and that
the
> > > > >>>> launcher
> > > > >>>> is expected to call ExceptionDescribe() if it wants any details to
be
> > > > >>>> printed.
> > > > >>>>
> > > > >>>> So from what you have said below, IMHO we need to:
> > > > >>>> - Change DRLVM to not print stack trace if there is an uncaught
> > > > >>>> exception at
> > > > >>>> shutdown.
> > > > >>>> - If necessary, change the launcher to make sure
ExceptionDescribe() is
> > > > >>>> called
> > > > >>>> before DestroyJavaVM().
> > > > >>>>
> > > > >>>> Does that sound right?
> > > > >>>>
> > > > >>>> Regards,
> > > > >>>> Oliver
> > > > >>>>
> > > > >>>> [1]
> > > > >>>> #include <jni.h>
> > > > >>>> main() {
> > > > >>>> JNIEnv *env;
> > > > >>>> JavaVM *jvm;
> > > > >>>> jint result;
> > > > >>>> jclass cls;
> > > > >>>> jmethodID mid;
> > > > >>>>
> > > > >>>> JavaVMInitArgs vmargs;
> > > > >>>> vmargs.version = 0x00010002;
> > > > >>>> vmargs.nOptions = 0;
> > > > >>>> vmargs.ignoreUnrecognized = JNI_TRUE;
> > > > >>>>
> > > > >>>> result=JNI_CreateJavaVM(&jvm, (void**)&env, &vmargs);
> > > > >>>>
> > > > >>>> if (result<0) {
> > > > >>>> fprintf(stderr, "Cannot create JavaVM\n");
> > > > >>>> exit(1);
> > > > >>>> }
> > > > >>>>
> > > > >>>> cls = (*env)->FindClass(env, "TestClass");
> > > > >>>>
> > > > >>>> if(cls == NULL)
> > > > >>>> {
> > > > >>>> printf("ERROR: FindClass failed.\n");
> > > > >>>> goto destroy;
> > > > >>>> }
> > > > >>>>
> > > > >>>> mid = (*env)->GetStaticMethodID(env, cls, "main",
> > > > >>>> "([Ljava/lang/String;)V");
> > > > >>>> if(mid==NULL)
> > > > >>>> {
> > > > >>>> printf("ERROR: GetStaticMethodID call failed.\n");
> > > > >>>> goto destroy;
> > > > >>>> }
> > > > >>>>
> > > > >>>> (*env)->CallStaticVoidMethod(env, cls, mid, NULL);
> > > > >>>>
> > > > >>>> destroy:
> > > > >>>> (*jvm)->DestroyJavaVM(jvm);
> > > > >>>> }
> > > > >>>>
> > > > >>>>
> > > > >>>>
> > > > >>>> Evgueni Brevnov wrote:
> > > > >>>>
> > > > >>>>> Hi All,
> > > > >>>>>
> > > > >>>>> I'm almost done with the implementation of Invocation API for
DRLVM.
> > > > >>>>> While testing it I ran into a problem when an exception is printed
> > > > >>>>> twice. I created a simple application which just throws an error
and
> > > > >>>>> it is not handled by any exception handler:
> > > > >>>>>
> > > > >>>>> public class Test {
> > > > >>>>> public static void main(String [] args) {
> > > > >>>>> throw new Error("my");
> > > > >>>>> }
> > > > >>>>> }
> > > > >>>>>
> > > > >>>>> In this case the launcher calls env->ExceptionDescribe() before
> > > > >>>>> destroying VM. Then it calls DestroyJavaVM() which identifies
> > > > >>>>> unhanded exception and calls an uncaught exception handler (see
> > > > >>>>> java.lang.Thread.getUncaughtExceptionHandler()) for the current
> > > > >>>>> thread. By default the handler prints the exception one more time.
> > > > >>>>> That's definitely differs from RI where the exception is printed
out
> > > > >>>>> only once.
> > > > >>>>>
> > > > >>>>> To identify where the problem is I created another simple test and
> > > > >>>>> runs it on RI and DRLVM:
> > > > >>>>>
> > > > >>>>> public class Test {
> > > > >>>>>
> > > > >>>>> static class MyHandler implements
Thread.UncaughtExceptionHandler {
> > > > >>>>> public void uncaughtException(Thread t, Throwable e) {
> > > > >>>>> System.out.println("My Handler Called!!!");
> > > > >>>>> }
> > > > >>>>> }
> > > > >>>>>
> > > > >>>>> public static void main(String [] args) {
> > > > >>>>> Thread.currentThread().setUncaughtExceptionHandler(new
> > > > >>>>> MyHandler());
> > > > >>>>> throw new Error("my");
> > > > >>>>> }
> > > > >>>>> }
> > > > >>>>>
> > > > >>>>> Here is the output:
> > > > >>>>>
> > > > >>>>> RI: java.exe Test
> > > > >>>>> My Handler Called!!!
> > > > >>>>>
> > > > >>>>> DRLVM: java.exe Test
> > > > >>>>> java/lang/Error : my
> > > > >>>>> at Test.main (Test.java: 12)
> > > > >>>>> My Handler Called!!!
> > > > >>>>>
> > > > >>>>> As you can see RI doesn't print exception stack trace at all. But
> > > > >>>>> DRLVM does. To be precise the launcher does. So we need to fix the
> > > > >>>>> launcher.....
> > > > >>>>>
> > > > >>>>> Note: The behaviour of DRLVM you have may differ from listed above
> > > > >>>>> since all experiments were done on my local workspace with
Invocation
> > > > >>>>> API implemented.
> > > > >>>>>
> > > > >>>>>
---------------------------------------------------------------------
> > > > >>>>> Terms of use : http://incubator.apache.org/harmony/mailing.html
> > > > >>>>> To unsubscribe, e-mail: [EMAIL PROTECTED]
> > > > >>>>> For additional commands, e-mail: [EMAIL PROTECTED]
> > > > >>>>>
> > > > >>>>>
> > > > >>>>>
> > > > >>>> --
> > > > >>>> Oliver Deakin
> > > > >>>> IBM United Kingdom Limited
> > > > >>>>
> > > > >>>>
> > > > >>>>
---------------------------------------------------------------------
> > > > >>>> Terms of use : http://incubator.apache.org/harmony/mailing.html
> > > > >>>> To unsubscribe, e-mail: [EMAIL PROTECTED]
> > > > >>>> For additional commands, e-mail: [EMAIL PROTECTED]
> > > > >>>>
> > > > >>>>
> > > > >>>>
> > > > >>>
---------------------------------------------------------------------
> > > > >>> Terms of use : http://incubator.apache.org/harmony/mailing.html
> > > > >>> To unsubscribe, e-mail: [EMAIL PROTECTED]
> > > > >>> For additional commands, e-mail: [EMAIL PROTECTED]
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >
> > > > >
> > > >
> > > > --
> > > > Oliver Deakin
> > > > IBM United Kingdom Limited
> > > >
> > > >
> > > > ---------------------------------------------------------------------
> > > > Terms of use : http://incubator.apache.org/harmony/mailing.html
> > > > To unsubscribe, e-mail: [EMAIL PROTECTED]
> > > > For additional commands, e-mail: [EMAIL PROTECTED]
> > > >
> > > >
> > >
> >
> > ---------------------------------------------------------------------
> > Terms of use : http://incubator.apache.org/harmony/mailing.html
> > To unsubscribe, e-mail: [EMAIL PROTECTED]
> > For additional commands, e-mail: [EMAIL PROTECTED]
> >
> >
>
> ---------------------------------------------------------------------
> Terms of use : http://incubator.apache.org/harmony/mailing.html
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
>
---------------------------------------------------------------------
Terms of use : http://incubator.apache.org/harmony/mailing.html
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
---------------------------------------------------------------------
Terms of use : http://incubator.apache.org/harmony/mailing.html
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
