Well, this is unfortunate. As I stated earlier, I fail to see how depending on constant version numbers (not version ranges) fall under the scope of "version selection". Was this case considered/discussed in depth?
Not everyone is sold on version ranges (e.g. the vast majority of Maven artifacts I've seen depend on constant versions) and I think this would go a long way towards solving the original "classpath hell" problem. Gili On 2016-08-31 2:55 PM, Neil Bartlett [via jigsaw-dev] wrote: > Gili, > > As Alex points out: your use-case can be supported in Java 9 but only > with the addition of custom ClassLoaders, or by using an existing > ClassLoader-based module system such as OSGi. > > The same is also true of Java 8, and Java 7, etc. > > Regards, > Neil > > > > On 31 Aug 2016, at 19:29, Alex Buckley <[hidden email] > </user/SendEmail.jtp?type=node&node=5713366&i=0>> wrote: > > > > On 8/31/2016 10:56 AM, cowwoc wrote: > >> I recently became aware of the fact that the Jigsaw specification > declared > >> "version-selection" as a non-goal. While I understand how we ended > up here, > >> I am hoping that you were able to support the following (very common) > >> use-case: > >> > >> * Module "HelloWorld" depends on modules "Guava" and "JSoup". > >> * Module "Guava" depends on module slf4j version 1 (requires but > does not > >> export it). > >> * Module "JSoup" depends on module slf4j version 2 (requires but > does not > >> export it). > >> * slf4j version 2 and is not backwards-compatible with version 1. > >> > >> What happens at runtime? Will Jigsaw (out of the box, without > 3rd-party > >> tools like Maven or OSGI) be smart enough to provide different > versions of > >> slf4j to "Guava" and "JSoup"? > > > > (You mean Guava/JSoup requires slf4j version 1/2 and does not > "re-export" it a.k.a. 'requires public'.) > > > > This use case isn't possible on JDK 8 for JARs on the classpath, and > it's not supported on JDK 9 for modular JARs on the modulepath: > > > > - If you have two versions of a modular JAR slf4j.jar in different > directories on the modulepath, then the first one to be found will > dominate, and that's what will be resolved for both Guava and JSoup. > > > > - If you have two modular JARs slf4j_v1.jar and slf4j_v2.jar on the > modulepath, and Guava requires slf4j_v1 and JSoup requires slf4j_v2, > then launching 'java -m HelloWorld' will fail. The boot layer will > refuse to map the "same" packages from different slf4j_v* modules to > the application class loader. > > > > The use case _is_ supported on JDK 9 for modular JARs loaded into > custom loaders of custom layers. That is, the Java Platform Module > System is perfectly capable of supporting the use case -- please see > any of my "Jigsaw: Under The Hood" presentations. The use case just > isn't supported "out of the box" by the 'java' launcher for JARs on > the modulepath. > > > > Alex > > > > ------------------------------------------------------------------------ > If you reply to this email, your message will be added to the > discussion below: > http://jigsaw-dev.1059479.n5.nabble.com/Multiple-versions-of-a-non-exported-dependency-tp5713364p5713366.html > > > To unsubscribe from Multiple versions of a non-exported dependency, > click here > <http://jigsaw-dev.1059479.n5.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=5713364&code=Y293d29jQGJicy5kYXJrdGVjaC5vcmd8NTcxMzM2NHwxNTc0MzIxMjQ3>. > NAML > <http://jigsaw-dev.1059479.n5.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml> > > -- View this message in context: http://jigsaw-dev.1059479.n5.nabble.com/Multiple-versions-of-a-non-exported-dependency-tp5713364p5713367.html Sent from the jigsaw-dev mailing list archive at Nabble.com.
