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From: Martin Gregorie <martin@address-in-sig.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: dealing with ClassLoaders...
Date: Fri, 1 Aug 2014 21:45:10 +0000 (UTC)
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On Fri, 01 Aug 2014 21:10:07 +0000, Andreas Leitgeb wrote:

> Andreas Leitgeb <avl@auth.logic.tuwien.ac.at> wrote:
>> Martin Gregorie <martin@address-in-sig.invalid> wrote:
>>> public class MAClassLoader extends ClassLoader {
>>   [ no snip ]
>>> }
>>> I hope this is useful info.
> 
> On further examination, I think it isn't as simple as that. Essentially,
> this "empty" ClassLoader-subclass would pass everything through to the
> parent classloader (or the pre-
> mordial one, absent a parent) and thus not be associated to any of the
> classes loaded through it, thus provide no isolation at all.
>
Your requirements would seem to be as bit different from mine, which were 
purely to package a number of programs (some Swing apps, some pure 
command-line apps, all accessing a single PostgreSQL database instance) 
into one convenient file and to be able to run them without needing to 
unpack the distribution file. There is almost never any need to run more 
than one of these programs at a time by any user/on any PC. So, as none 
of these ever share a JVM the most convenient way to do this was to pack 
them all into a jar file and use that very simple class loader as a way 
to select and run one of the programs in it. I do not have any of the 
your process isolation requirements which is why I can get away with such 
a simple class loader. Once the top level class defining the program to 
be run has been loaded I don't care what class loader is used to pull in 
the other classes it needs - in fact I'd be surprised if the default 
class loader *wasn't* used for that.  


-- 
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |