Rethrowing an exception via JNI ?

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Paul J. Lucas - 30 Nov 2005 03:49 GMT

    What's the proper way to rethrow an exception in JNI?

        int result = env->CallIntMethod(
        obj, methID, arg
        );
        if ( jthrowable t = env->ExceptionOccurred() ) {
        env->ExceptionClear(); // should this be called here?
        env->Throw( t ); // what about this?
        }

    The JNI documetation I've seen doesn't talk about this. If all
    one wants to to is "notice" the exception (but not really
    "catch" it), what does one do? I don't really want to "catch"
    it, just pass it back to the Java side.

    - Paul

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Gordon Beaton - 30 Nov 2005 07:01 GMT

>     What's the proper way to rethrow an exception in JNI?
>
[quoted text clipped - 10 lines]
>     "catch" it), what does one do? I don't really want to "catch"
>     it, just pass it back to the Java side.

If you do ExceptionClear(), you need to use Throw(t) to re-raise the
exception just like in your example.

If you just want to notice the exception, then don't clear it and it
stays active (and you don't need to re-throw it). Note though that you
aren't allowed to do much of anything with the JVM while the exception
is active.

Some information at the bottom of this page:
http://java.sun.com/j2se/1.5.0/docs/guide/jni/spec/design.html

Note that ExceptionDescribe() might also clear the exception:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4067541

/gordon

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Rethrowing an exception via JNI ?

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