Le 03/02/2013 19:27, Denis Kudriashov a écrit :
> 2013/2/3 Miguel Moquillon <miguel.moquillon@gmail.com
> <mailto:miguel.moquillon@gmail.com>>
>
> And the Java people are preparing to throw away the classloaders
> mechanism with Jigsaw that will be in Java 9. (The classloading is a
> brittle and error-prone mechanism.) The aim of jigswa is to design
> and implement a new module system for the Java SE platform and to
> apply that sys­tem to the plat­form it­self and to the JDK (more
> information in the project homepage
> http://openjdk.java.net/projects/jigsaw/
> <http://openjdk.java.net/projects/jigsaw/>).
>
> Miguel
>
>
> I know about this. But let's talk about pharo. Now pharo can't do
> this. You can't have two versions of same package at same time in
> image. So how we can implement it? And do this is really important?

IMHO, it is not important and should be avoided because it is error-prone (what is the actual version used by the objects?). This can even be a nightmare with a lot of dependencies when an error occurs.
Don't forget: keep things simple (it is always more easily to build too more complex systems).
Having a program depending on a package in two different versions at the same time in an image is in my opinion a design error. And if your program depends on some tiers-party packages that depend on a different version of a same package, then you should decide for the more recent one (or according to other heuristic) and fix, if needed, the dependency in the others packages. This is more easy to do with Pharo than with Java.
Even in Java, we take care to avoid these situations by using a dependency exclusion with Maven.

Miguel