Can't instantiate anonymous class more than 16 times

[Rémi Forax]

Le 11/08/2009 21:03, Wei Yin Teo a écrit :
>
>
> On 11 Aug 2009, at 02:09, Rémi Forax wrote:
>
>> Le 11/08/2009 00:49, Wei Yin Teo a écrit :
>>> Right, I think the work around is working because we are getting a 
>>> new class and we don't hit the threshold.
>>>
>>> The magic number 15 is the ReflectionFactory.inflationThreshold() as 
>>> we can see in the class NativeConstructorAccessorImpl
>>>
>>>
>>> public Object newInstance(Object[] args) ...    {
>>> if (++numInvocations > ReflectionFactory.inflationThreshold()) {
>>>             ConstructorAccessorImpl acc = (ConstructorAccessorImpl)
>>> new MethodAccessorGenerator().
>>>                     generateConstructor(...)
>>> ...
>>>
>>> I think the AnonymousClassLoader mangles the class name from 
>>> InstanceTest to InstanceTest/123456. However the generated 
>>> ConstructorAccessor would interpret that as a class 
>>> InstanceTest.123456 instead of InstanceTest and the JVM would then 
>>> try to load InstanceTest/123456.class. Of course it can't be found 
>>> anywhere. I suppose Class.forName() should not be able to locate it 
>>> in the system(permGen?) name space, either.
>>
>> You're right the problem is in package sun.reflect but the problem is not
>> a dot transformed to a slash or vice-versa.
>>
>> Class.forName() uses class loader mechanism, and anonymous class 
>> aren't registered
>> in any classloader cache. The reflection factory (here 
>> MethodAccessorGenerator)
>> generates a bytecode with the name of the anonymous class in the 
>> constant pool
>> to be able to call the constructor of the anonymous class.
>> When this bytecode is loaded, the VM tries to resolve it with a 
>> classloader mechanism,
>> so it fails throwing a NoClassDefFound.
>>
>> So, short time workaround:
>> use -Dsun.reflect.noInflation=false
>
> Apparently, this doesn't work as you can see the above newInstance(..) 
> calls MethodAccessorGenerator().generateConstructor(...) when the 
> threshold is exceeded. Shouldn't it call 
> ReflectionFactory.newConstructorAccessor(), which is guarded by the 
> system property, instead?

oup, sorry
-Dsun.reflect.noInflation=true

Rémi
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