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Using different versions of jar files

P Lavti
Ranch Hand

Joined: Mar 27, 2007
Posts: 65
I have two version of my jar file in jboss lib folder. Can I use API's of both the jar files as and when needed from my war file? If yes then how will I differentiate in the code for which version of jar file to use?

Please let me know if you need more details.

Thanks!


-P Lavti<br />SCJP 5.0 (88%)
Ulf Dittmer
Marshal

Joined: Mar 22, 2005
Posts: 41180
    
  45
You have no control over which one of the two will be used; it's a bad idea. Why are you doing this?

If you need to support two versions of the API with identical class names, keep the jar files outside of the lib folder, and create your own classloader that knows about them and their differences.


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P Lavti
Ranch Hand

Joined: Mar 27, 2007
Posts: 65
I dont ahve any idea about creating a customized class loaders.
Can you please tell me some good tutorials and examples available on net, which i can use for my reference.
Ulf Dittmer
Marshal

Joined: Mar 22, 2005
Posts: 41180
    
  45
If you're not familiar with class loaders, this may be a tall order. The SecurityFaq links to a few articles on the subject; I particularly recommend the first one titled "CLASS LOADERS AS A NAMESPACE MECHANISM".

An alternate solution -if you have a limited number of API versions to support- might be to include the API version somewhere in the package name hierarchy. Then the code would explicitly use different classes (representing different API versions) as appropriate.
 
I agree. Here's the link: http://aspose.com/file-tools
 
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