Re: Re: subclass and superclass transformation question

Just load the parent classes/interfaces as resources and analyse them 
with ASM. If you have to perform modifications, you should do what 
Eugene suggested: Prepare the transformations virtually and apply them 
if the classloader eventually loads the parent classes/interfaces.

Regards,
Marcel

Tronje Krop schrieb:
> I'm currently not using the java agent, but I like to do son in
> future.
>
> My problem concerning the order of class loading is, that I need
> at least to analyse parent classes and interfaces before trans-
> forming the subclasses.
>
> But how can I do this without forcing the class loader to load
> interfaces and parent classes. Any suggestion?
>
> CU Tronje
>
> Eugene Kuleshov wrote:
>   
>>   I wouldn't advise loading classes from the agent. Instead you should
>> be able to prepare required transformations "virtually" when
>> analyzing/loading subclasses, save some state and do the actual
>> transformation when parent is actually loaded by JVM.
>>
>>   regards,
>>   Eugene
>>
>>
>> On Tue, Feb 23, 2010 at 10:01 AM, Rémi Forax <[email protected]> wrote:
>>     
>>> Hi Peter,
>>>
>>> Le 23/02/2010 14:49, Peter Veentjer a écrit :
>>>       
>>>> I have a question about the details of superclass/subclass
>>>> transformations using a Java agent.
>>>>
>>>> If there is a class Fruit and a subclass Apple, and if a new Apple is
>>>> created before the Fruit class is used in the JVM.
>>>> What is the exact order of classes loaded in the Java agent?
>>>>
>>>> My experience is that the Apple class is transformed before the Fruit
>>>> class is transformed. Is this correct?
>>>>
>>>>         
>>> Yes, the VM read the transformed class, find the super class and load it,
>>> so superclass are loaded after class if there aren't loaded before.
>>>
>>> But you can load the superclass in the agent :)
>>> you have the classloader and you can find the superclass in the classfile.
>>> Just be careful about synchronisation, jdk7 classloading is done in
>>> parallele.
>>>
>>>
>>>       
>>>> And is there any way to force to load the super class (Fruit) is
>>>> transformed before the subclass Apple is transformed?
>>>>
>>>> I have the impression that the Java agent technology is very limited
>>>> and that the only way to solve these issues is
>>>> to do a static transformation. The big problem is that it makes the
>>>> system much harder to work with from an IDE; normally
>>>> you only need to register some javaagent and you are done. But adding
>>>> a postcompilation step is much harder.
>>>>
>>>>         
>>> Rémi
>>>
>>>
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>>>
>>>       
>
>

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