Re: JNI assertion failure

[Archie Cobbs]

Archie Cobbs wrote:
> With Classpath 0.16, trying to run a very simple Swing demo under JCVM,
> I get a JNI assertion failure in a call to GetIntField(), because the 
> object
> type and the fieldID are not compatible:
>
>    gnu/java/awt/peer/gtk/address@hidden not instance of 
> gnu/java/awt/peer/gtk/GtkGenericPeer
>
> Here is the relevant stack trace snippet:
>
> #7  0x29f862d7 in 
> Java_gnu_java_awt_peer_gtk_GdkGraphics_initState__Lgnu_java_awt_peer_gtk_GtkComponentPeer_2 
> (env=0x107ed6a0, obj=0x29795698, peer=0x2979569c)
>     at gnu_java_awt_peer_gtk_GdkGraphics.c:154

Hmm, no response.. can anyone else confirm this problem??

It looks like this code is completely broken, because
it's trying to save a pointer in a field that doesn't
exist. Line 154 of gnu_java_awt_peer_gtk_GdkGraphics.c says:

  NSA_SET_PTR (env, obj, g)

but "obj" is a gnu/java/awt/peer/gtk/GdkGraphics object, not
a gnu/java/awt/peer/gtk/GtkGenericPeer object, the class that
contains the "native_state" field.

I'm not familiar with this code so I could be completely
misunderstanding something. But it seems obviously wrong,
and on VM's that don't check proper JNI usage will result
in random memory corruption.

I'd appreciate a quick confirmation from another set of eyes...

Thanks,
-Archie

__________________________________________________________________________
Archie Cobbs      *        CTO, Awarix        *      http://www.awarix.com