Oliver, No problems. I agree.
Evgueni On 10/13/06, Oliver Deakin <[EMAIL PROTECTED]> wrote:
Hi Evgueni, Ive taken a look at the patch - it looks fine to me. My only comment on: //(*jvm)->DetachCurrentThread(jvm); is that I believe we need this line to be uncommented to get the correct behaviour when running with the IBM VME. As such, I would suggest uncommenting this line in the Harmony launcher for those using the VME. Do you agree? Regards, Oliver Evgueni Brevnov 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] > > -- 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]
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