RFR(S): 8191229: serviceability/jvmti/GetOwnedMonitorInfo/GetOwnedMonitorInfoTest.java fails with NoClassDefFoundError

[David Holmes]

On 8/12/2017 11:40 AM, Daniel D. Daugherty wrote:
> I would not do the JVM/TI SetEventNotificationMode() call i JNI_OnLoad().

I agree. I had not really considered the dual use of this one library as 
both a JNI lib and a JVM TI agent lib.

In that regard the NULL check is fine.

Thanks,
David

> Dan
> 
> 
> On 12/7/17 8:38 PM, Chris Plummer wrote:
>> Hi Yasumasa,
>>
>> That would work, but let me see what David and Serguei think. I 
>> believe normally we enable events in Agent_Initialize(), so don't want 
>> to switch around something that's working if it's not what we really 
>> want.
>>
>> thanks,
>>
>> Chris
>>
>> On 12/7/17 5:13 PM, Yasumasa Suenaga wrote:
>>> Hi Chris,
>>>
>>> Thanks! I did not see that.
>>>
>>> IMHO, you can move SetEventNotificationMode() to JNI_OnLoad(). If so,
>>> we ensure that CheckLockObject() is called after all initialization is
>>> completed.
>>> We can keep jvmtiEnv instance.
>>>
>>>
>>> Yasumasa
>>>
>>>
>>>
>>> 2017-12-08 1:51 GMT+09:00 Chris Plummer <chris.plummer at oracle.com>:
>>>> Hi Yasumasa,
>>>>
>>>> It is safe in my version because I move it to a global ref. See the
>>>> NewGlobalRef() call in my webrev.
>>>>
>>>> thanks,
>>>>
>>>> Chris
>>>>
>>>>
>>>> On 12/7/17 6:14 AM, Yasumasa Suenaga wrote:
>>>>> Hi Chris,
>>>>>
>>>>> I added testcase of GetOwnedMonitorInfo in JDK-8185164.
>>>>> I have concern your change to cache the result of FindClass().
>>>>>
>>>>> According to [1], FindClass() calls find_class_from_class_loader(), it
>>>>> returns JNI local value.
>>>>> Is it safe to cache?
>>>>>
>>>>> So I called FindClass each time in original commit.
>>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Yasumasa
>>>>>
>>>>>
>>>>> [1]
>>>>> http://hg.openjdk.java.net/jdk/hs/file/32fd4be602d5/src/hotspot/share/prims/jvm.cpp#l3450 
>>>>>
>>>>>
>>>>>
>>>>> On 2017/12/07 16:44, Chris Plummer wrote:
>>>>>> New webrev:
>>>>>>
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8191229
>>>>>> http://cr.openjdk.java.net/~cjplummer/8191229/webrev.01/
>>>>>>
>>>>>> testClass now initialized from JNI_OnLoad(), and use memset to clear
>>>>>> callbacks. Also updated to use JVMTI_VERSION_9 when calling GetEnv().
>>>>>>
>>>>>> thanks,
>>>>>>
>>>>>> Chris
>>>>>>
>>
>