JNI Exits with SIGUSR2

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arunmozhian@gmail.com - 23 Nov 2005 20:01 GMT

Hello,
I'm trying to debug an issue with a Java program which involves/uses
JNI too !
In short, I'm not able to isolate the problem (whether the issue is
in Java or JNI!),
since for any issue all I get is a User Signal 2.
Sometimes I've had issues in Java which ended in User Signal 2
anyway !

Any ptrs on when does Java use/throw a User Signal 2 (especially
with JNI) ?
and how to go about debugging the same will be really helpful.

Any resources/pointers on JNI debugging will also be helpful ?

Thanks,
Arun

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Stefan Schulz - 24 Nov 2005 10:24 GMT

On Wed, 23 Nov 2005 12:01:34 -0800, arunmozhian wrote:

> Hello,
> I'm trying to debug an issue with a Java program which involves/uses
[quoted text clipped - 10 lines]
>
> Any resources/pointers on JNI debugging will also be helpful ?

AFAIK, the JDK does not use any system signals it does not provide its own
handlers for. The fact that the signal is raised seems to me like an issue
between the JNI and whatever native libraries used. Take a look at the
crash trace of the java process, and make sure that the signal is not
raised in your (or whatever native libraries you use) code.

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arunmozhian@gmail.com - 28 Nov 2005 16:22 GMT

There's no crash generated. All that is generated is a User Signal 2.
And I've verified that
my native libs do not handle/raise SIGUSR2. I believe the JVM uses
SIGUSR2 for Garb. coll'n.

-- Arun

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Thomas Fritsch - 28 Nov 2005 17:01 GMT

> AFAIK, the JDK does not use any system signals it does not provide its own
> handlers for.

I don't agree here.
The JDK contains some signal-related classes (Signal, SignalHandler,
NativeSignalHandler in package sun.misc) which map pretty straight to
the C-functions raise() and signal(). This fact makes me think that Sun
very well may raise/handle signals somewhere in its Java code.

See also
http://www.google.com/search?q=%22Signal.java%22+%2B%22package+sun.misc%22

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JNI Exits with SIGUSR2

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