Re: changing class path at run time

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#173

From: Shankar Unni
Date: Mon, 03 Apr 2006 19:26

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George Xavier wrote:

> Anyway to get back to the issue which started this all:  looks like the
> runtime never revisits the value of java.class.path after the VM has
> started.  Wonder why.

That's definitely true. The system class loader reads the value of this 
property *once*, and that's it.

It probably has to do with the overhead of getting the value and parsing 
it, and it would be rather expensive to do that for each class loaded 
(even a trivial program loads over a hundred classes).

If you want a dynamic system class path, you need to interpose a 
URLClassLoader in between. Or create your own class loader class (not 
hard to do) which can extend from URLClassLoader, and make it the system 
class loader by passing in 
"-Djava.system.class.loader=your.classloader.class.Name".

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