Here is the new fix in which FieldMonitor will write to
TestPostFieldModification, to inform the latter to quit, as suggested bu
Jaroslav
http://cr.openjdk.java.net/~sjiang/JDK-8007710/01/
Thanks,
Shanliang
shanliang wrote:
shanliang wrote:
Jaroslav Bachorik wrote:
On 11.2.2014 16:31, shanliang wrote:
Staffan Larsen wrote:
Hi Shanliang,
I can’t quite see how the test can fail in this way. When the
ClassPrepareEvent happens, the debuggee will be suspended. So when
addFieldWatch() is called, the debuggee should not have moved.
I am not expert of jdi so I may miss something here. I checked the
failure trace and saw the report exception happen when FieldMonitor
received ClassPrepareEvent and was doing addFieldWatch.
FieldMonitor did
call "vm.resume()" before treating events.
AFAICS, calling vm.resume() results in an almost immediate debuggee
death. The gc() invoking thread "d" is flagged as a deamon and as
such doesn't prevent the process from exiting. The other thread is
not a daemon but will finish in only few cycles.
I looked at the class com.sun.jdi.VirtualMachine, here is the Javadoc
of the method "resume":
/**
* Continues the execution of the application running in this
* virtual machine. All threads are resumed as documented in
* {@link ThreadReference#resume}.
*
* @throws VMCannotBeModifiedException if the VirtualMachine is
read-only - see {@link VirtualMachine#canBeModified()}.
*
* @see #suspend
*/
void resume();
My understanding is that the debuggee resumes to work after this
call, instead to die?
In fact the problem is here, the vm (TestPostFieldModification) should
not die before FieldMonitor finishes addFieldWatch.
Shanliang
I reproduced the bug by add sleep(1000) after vm.resume() but before
calling eventQueue.remove();
It looks like some kind of synchronization between the debugger and
the debuggee is necessary. But I wonder if you should better use the
process.getOuptuptStream() to write and flush a message for the
debugee indicating that it can exit. And in the debugee you would
just do System.in.read() as the last statement in the main() method.
Seems more robust than involving files.
It could work, but creating a file in the testing directory should
have no issue, but yes maybe less performance.
Thanks,
Shanliang
Cheers,
-JB-
Thanks,
Shanliang
One problem I do see with the test is that it does not wait for a
VMStartEvent before setting up requests. I’m not sure if that could
cause the failure in the bug report, though.
/Staffan
On 11 feb 2014, at 15:13, shanliang <shanliang.ji...@oracle.com>
wrote:
Hi ,
The problem could be that FieldMonitor did not have enough time to
"addFieldWatch" but the vm to monitor (TestPostFieldModification)
was
already ended.
So we should make sure that TestPostFieldModification exits after
FieldMonitor has done necessary. The solution proposed here is that
FieldMonitor creates a file after adding field watching, and
TestPostFieldModification quits only after finding the file.
web:
http://icncweb.fr.oracle.com/~shjiang/webrev/8007710/00/
bug:
https://bugs.openjdk.java.net/browse/JDK-8007710
Thanks,
Shanliang
