RFR(10)(XXS): 8175341: "java/util/Arrays/ParallelPrefix.java" Crash Internal Error ...diagnosticCommand.cpp...assert(k != __null) failed: FinalizerHistogram class is not accessible

[Chris Plummer]

On 3/6/17 5:58 PM, David Holmes wrote:
> On 7/03/2017 11:51 AM, David Holmes wrote:
>> Hi Chris,
>>
>> On 7/03/2017 10:57 AM, Chris Plummer wrote:
>>> Hi,
>>>
>>> Please review the following simple fix. Explanation of the cause and 
>>> the
>>> fix are in the CR. Testing so far has only been done with
>>> serviceability/dcmd/gc/FinalizerInfoTest.java as described in the CR. I
>>> think the addition of JPRT push testing will be sufficient.
>>>
>>> http://cr.openjdk.java.net/~cjplummer/8175341/webrev.00/webrev.hotspot/
>>> https://bugs.openjdk.java.net/browse/JDK-8175341
>>
>> Looking at the other potentially-exception-throwing actions in that DCmd
>> and others, I think a simple delete of the assert and change:
>>
>>  425     vmSymbols::finalizer_histogram_klass(), THREAD);
>>
>> to
>>
>>  425     vmSymbols::finalizer_histogram_klass(), CHECK);
>>
>> would suffice. Something upstream has to handle potential errors and the
>> pending exception in any case.
>
> Oops! This explains why no exception:
>
> 424   Klass* k = SystemDictionary::resolve_or_null(
>  425     vmSymbols::finalizer_histogram_klass(), THREAD);
>
> it uses resolve_or_null, not resolve_or_fail! I think it should use 
> the latter and simply throw like the other Dcmds.
>
Ok. That seems to work. Bit of a hurry here before I step out, so 
trimmed diff is inline:

-  Klass* k = SystemDictionary::resolve_or_null(
-    vmSymbols::finalizer_histogram_klass(), THREAD);
-  assert(k != NULL, "FinalizerHistogram class is not accessible");
+  Klass* k = SystemDictionary::resolve_or_fail(
+    vmSymbols::finalizer_histogram_klass(), true, CHECK);
+  if (k == NULL) {
+    return;
+  }

I'm a bit unclear about THREAD vs CHECK. They both seem to work. Not 
sure which is correct here.

When I forced an exception by dropping the last character of the class 
name, here's what I see in the test output:

  stderr: [java.lang.NoClassDefFoundError: java/lang/ref/FinalizerHistogra
]

cheers,

Chris
> David
>
>> Thanks,
>> David
>>
>>> thanks,
>>>
>>> Chris
>>>