On 2017-04-21, Ralph Goers wrote: > I have not started work on this yet, but from looking at > http://blog.joda.org/2017/04/java-9-modules-jpms-basics.html > <http://blog.joda.org/2017/04/java-9-modules-jpms-basics.html> it > seems we are going to have problems with a) plugins that are in > different jars (modules) that use the same namespace and b) log4j-core > as it currently exists.
> Item b is a problem because the module-info for log4j-core should have > a requires ONLY for log4j-api. For example, I’m not sure how we can > have an optional dependency on Jackson. requires static module-name-of-jackson; http://cr.openjdk.java.net/~mr/jigsaw/spec/lang-vm.html section 1.1.1 The requires keyword may be followed by the modifier static. This specifies that the dependence, while mandatory at compile time, is optional at run time. Of course "requires static" captures this way more clearly than "require optional" which was proposed intially http://openjdk.java.net/projects/jigsaw/doc/topics/optional.html :-) Without knowing the structure of log4j too well I agree the strict package hierarchies mandated by JPMS will be a problem. Probably for many other projects with more than one artifact as well. Stefan
