Pass a pointer to JNI_GetCreatedJavaVMs() instead of null / review please (original) (raw)

David Holmes david.holmes at oracle.com
Tue May 8 03:06:52 UTC 2012

Hi Kumar,

On 8/05/2012 6:21 AM, Kumar Srinivasan wrote:

Hi,

Please review http://cr.openjdk.java.net/~ksrini/7166955

Thanks for jumping on checking the return value. Actually hotspot can never return an error here so it was much less of an issue than I thought.

David

Thanks Kumar

On 07/05/2012 16:45, Kumar Srinivasan wrote: Hi David, Deven, Alan,

The spec doesn't say anything but the implementation does check for NULL. I think this is a spec issue rather than a code issue (and I think hotspot-runtime owns the JNI spec so cc'ed). It is common practice for API's that take pointers like this to say "if buf is not NULL then the value of XXX is written into buf". Particularly as in this case there will only ever be at most 1 VM created per-process anyway.

I'm more concerned about the fact that the code doesn't even check if JNIGetCreatedVMs returns successfully! Ouch!, I will file a CR and fix this. I think HotSpot can only ever return JNIOK so it may only be a potential issue when running with another VM. -Alan

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