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From "Michał Kłeczek (XPro Sp. z o. o.)" <michal.klec...@xpro.biz>
Subject Re: OSGi
Date Mon, 30 Jan 2017 10:04:36 GMT
What I think Jini designers did not realize is that class loading can be 
treated exactly as any other capability provided by a (possibly remote) 
service.
Once you realize that - it is possible to provide a kind of a "universal 
container infrastructure" where different class loading implementations 
may co-exist in a single JVM.
What's more - these class loading implementations may be dynamic 
themselves - ie. it is a service that provides the client with a way to 
load its own (proxy) classes.

In other words: "there not enough Jini in Jini itself".

We have _all_ the required pieces in place:
- dynamic code loading and execution (ClassLoaders),
- security model and implementation that allows restricting rights of 
the downloaded code,
- and a serialization/deserialization which allows sending arbitrary 
data (and yes - code too) over the wire.

It is just the matter of glueing the pieces together.

Thanks,
Michal


Gregg Wonderly wrote:
> <snip>
> I am not an OSGi user.  I am not trying to be an OSGi opponent.  What I am trying to
say is that I consider all the commentary in those articles about TCCL not working to be just
inexperience and argument to try and justify a different position or interpretation of what
the real problem is.
>
> The real problem is that there is not one “module” concept in Java (another one is
almost here in JDK 9/Jigsaw).  No one is working together on this, and OSGi is solving problems
in a small part of the world of software.   It works well for embedded, static systems.  I
think OSGi misses the mark on dynamic systems because of the piecemeal loading and resolving
of classes.  I am not sure that OSGi developers really understand everything that Jini can
do because of the choices made (and not made) in the design.  The people who put Jini together
had a great deal of years of experience piecing together systems which needed to work well
with a faster degree of variability and adaptation to the environment then what most people
seem to experience in their classes and work environments which are locked down by extremely
controlled distribution strategies which end up slowing development in an attempt to control
everything that doesn’t actually cause quality to suffer.
>
> Gregg
>
>


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