Re: Error while creating instance

It's a well known error, a classloader issue.
After 16 call to the same constructor the reflection API decide to 
optimize the call
by producing a ad-hoc bytecodes.
But this optimisation fails because the classloader you write doesn't
follow the delegation pattern.
The common solution is to redefine findClass instead of loadClass.

cheers,
Rémi

Le 09/02/2010 22:56, [email protected] a écrit :
> I wrote my own class loader which changes classes of a certain type when
> loaded. The change works fine, however I have a problem with reflection. The
> framework I'm writing creates instances by reflection. The weird thing is that
> I'm able to create up to 16 new instances of the changed class, using
> class.newInstance(), and then it fails with the following exception:
>
> java.lang.IllegalAccessError: class sun.reflect.GeneratedConstructorAccessor2
> cannot access its superclass sun.reflect.ConstructorAccessorImpl
> 	at sun.misc.Unsafe.defineClass(Native Method)
> 	at sun.reflect.ClassDefiner.defineClass(ClassDefiner.java:45)
> 	at
> sun.reflect.MethodAccessorGenerator$1.run(MethodAccessorGenerator.java:381)
> 	at java.security.AccessController.doPrivileged(Native Method)
> 	at
> sun.reflect.MethodAccessorGenerator.generate(MethodAccessorGenerator.java:377)
> 	at
> sun.reflect.MethodAccessorGenerator.generateConstructor(MethodAccessorGenerator.java:76)
> 	at
> sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:30)
> 	at
> sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
> 	at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
> 	at java.lang.Class.newInstance0(Class.java:355)
> 	at java.lang.Class.newInstance(Class.java:308)
> ...
>
> I couldn't find much on this error on the net. It only happens when the class
> is changed by my classloader using asm. I'm hoping someone here can shed some
> light on this and how to solve it.
>
> Thanks,
>
> Shai
>

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