[udig-devel] jai is driving me cray

[Jesse Eichar]

We always use the JAI that is installed in the ext directory.  Where  
is this code being called from?  Every plugin that uses JAI must add  
the line:

Eclipse-BuddyPolicy: ext

In your manifest.mf file.

This states that the extensions in the JVM's lib/ext directory will  
be available on the classpath of that plugin.  It could be that the  
method you are using is getting the File from the wrong classloader  
(the lib one perhaps).

If you can give me some details about what you're doing I might be  
able to come up with a better answer.

Jesse


On Apr 4, 2007, at 6:28 AM, Andrea Antonello wrote:

>>> Hi folks, I have (once again) a problem with jai:
>>>
>>> java.lang.ClassCastException:
>>> com.sun.media.jai.imageioimpl.ImageReadWriteSpi
>>>     at
>>> javax.media.jai.OperationRegistry.registerServices 
>>> (OperationRegistry.java:2047)
>>>
>>>     at
>>> javax.media.jai.ThreadSafeOperationRegistry.registerServices 
>>> (ThreadSafeOperationRegistry.java:612)
>>>
>>>     at
>>> javax.media.jai.OperationRegistry.initializeRegistry 
>>> (OperationRegistry.java:365)
>>>
>>>     at javax.media.jai.JAI.<clinit>(JAI.java:560)
>>>
>>>
>>> So what is the best practice?
>>
>> The best practice is the harder to attain. You should have the JAI  
>> jars
>> installed directly into your JDK, and don't have them anywhere in the
>> classpath. Otherwise you're bound to issues as soon as a damned
>> classloader does not play exactly by the Sun rules. Sigh...
>
> Yes, but that gives me big troubles when I have to export a product. I
> usually somehow have some reference in it and when not it fails  
> because
> there is some dependency. I agree with the fact that this is a problem
> of mine and that I should know a bit better how exactly to do a clean
> and proper export of an eclipse product, but things would be much  
> easier
> if the lars could be put in the classpath and the .so in the  
> library path :)
>
>> The issue is that JAI is packaged as an extension, and it's sealed.
>> We still haven't tried hacking the official jars and remove the  
>> sealing
>> markers, but that would be an interesting test too (that is, to  
>> check if
>> this way JAI can be handled both in the JDK/JRE and in the  
>> classpath).
>
> Oh, that is something I didn't know, the sealing thing I mean. I
> remember there was also a download version for classpath use. Hmmm...
> I'll have to check.
>
> Thanks for the informations,
> Ciao
> Andrea
>
>
>
>
>
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