Hi,

It seems that plugin-loading code is somehow broken. There is some
discussion going on about this on
http://www.nabble.com/forum/ViewPost.jtp?post=10844164&framed=y .

On 6/5/07, Enzo Michelangeli <[EMAIL PROTECTED]> wrote:
> I have a question about the loading mechanism of plugin classes. I'm working
> with a custom URLFilter, and I need a singleton object loaded and
> initialized by the first instance of the URLFilter, and shared by other
> instances (e.g., instantiated by other threads). I was assuming that the
> URLFilter class was being loaded only once even when the filter is used by
> multiple threads, so I tried to use a static member variable of my URLFilter
> class to hold a reference to the object to be shared: but it appears that
> the supposed singleton, actually, isn't, because the method responsible for
> its instantiation finds the static field initialized to null. So: are
> URLFilter classes loaded multiple times by their classloader in Nutch? The
> wiki page at
> http://wiki.apache.org/nutch/WhichTechnicalConceptsAreBehindTheNutchPluginSystem
> seems to suggest otherwise:
>
>     Until Nutch runtime, only one instance of such a plugin
>     class is alive in the Java virtual machine.
>
> (By the way, what does "Until Nutch runtime" mean here? Before Nutch
> runtime, no class whatsoever is supposed to be alive in the JVM, is it?)
>
> Enzo
>
>

-- 
Doğacan Güney
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