[lang] Class loading

[Oliver Heger <ol...@oliver-heger.de>]

In [lang] there are a few places where Class.forName(String, boolean, 
ClassLoader) is used to load classes dynamically (e.g. in 
ClassUtils.getClass()).

According to the book "OSGi in action" (written by guys from the Felix 
community) it is recommended to use ClassLoader.loadClass() instead. The 
reason - IIUC - is that Class.forName() does a more aggressive caching; 
it is possible that the same Class object is returned even if a 
different class loader is passed in. This may cause trouble in 
environments like OSGi.

So should we switch to ClassLoader.loadClass() to be on the safe side? 
The only problem I see is that the API of ClassUtils.getClass() is 
pretty much tailored towards Class.forName(); it expects the same 
arguments. Especially the boolean initialize flag is not supported by 
ClassLoader.loadClass(). I am not sure whether this is really an issue, 
but there would be a slight change is the semantics of the getClass() 
method because initialization of the class could not be triggered 
directly any more.

WDYT?
Oliver

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Re: [lang] Class loading

[Gary Gregory <ga...@gmail.com>]

One thing to watch out for here is the loadClass expects a binary
name. I think forName does not, at least the Javadoc does not say so
(and I cannot experiment ATM, on my phone).

Gary

On Aug 25, 2012, at 14:58, Oliver Heger <ol...@oliver-heger.de> wrote:

> In [lang] there are a few places where Class.forName(String, boolean, ClassLoader) is used to load classes dynamically (e.g. in ClassUtils.getClass()).
>
> According to the book "OSGi in action" (written by guys from the Felix community) it is recommended to use ClassLoader.loadClass() instead. The reason - IIUC - is that Class.forName() does a more aggressive caching; it is possible that the same Class object is returned even if a different class loader is passed in. This may cause trouble in environments like OSGi.
>
> So should we switch to ClassLoader.loadClass() to be on the safe side? The only problem I see is that the API of ClassUtils.getClass() is pretty much tailored towards Class.forName(); it expects the same arguments. Especially the boolean initialize flag is not supported by ClassLoader.loadClass(). I am not sure whether this is really an issue, but there would be a slight change is the semantics of the getClass() method because initialization of the class could not be triggered directly any more.
>
> WDYT?
> Oliver
>
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> To unsubscribe, e-mail: dev-unsubscribe@commons.apache.org
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