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create fields in a class at runtime

 
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Hi all

OpenEjb creates some fields in session beans and entities at runtime or when the class is loaded in order to manage them for the better performance. Can anyone tell me how to do this and please give me a link or any article about this.

Thanks
 
Mohammad Norouzi
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any idea?
 
Rancher
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Check out the Javassist library. It can alter existing classes at runtime, or create entirely new ones.
 
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A classloader can modify the bytes that define a class as it's being loaded; this is the basis for "Aspect-Oriented Programming", for example.

I've been using the Javassist library a lot lately; it can be used to do this kind of thing. The key is that the class is modified BEFORE you load it in. Once the JVM loads a class, you can't modify it.
 
Ernest Friedman-Hill
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Curse you, Ulf!
 
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