Clojure 1.9 (and 1.8, and every other prior version of Clojure!) works with Java 9 due to the care that Java takes in retaining backward compatibility. Clojure 1.0 works just fine with Java 9.
However, there have been some changes that affect various tools, most prominently Leiningen and Boot. Leiningen has for a long time put the Clojure jar on the bootclasspath to make startup a little faster. Due to the new classloader and base module constraints, this doesn't work in Java 9 due to the use of a class outside the Java base module in core. In Clojure 1.9.0-beta1 we started lazy loading the code using the problematic class to sidestep this specific case. Also, Leiningen has made changes such that there is more flexibility in whether you put Clojure on the bootclasspath. Depending which version of lein and Clojure you are using, you may see this issue. I'd recommend using the latest version of both lein and Clojure to avoid it. There have also been changes in the standard classloader hierarchy in Java 9 that affect some of the dynamic classloader libraries (like dynapath, used by Leiningen and Boot). Those issues have been addressed but if you have an older version of any of those you can encounter those problems. There is a known issue related to the new module system in JDK9 and how Clojure chooses a method in a reflective call, in particular the Reflector may choose to invoke a module-private method of an implementation rather than the visible interface method. This violates the module system's constraints and throws an IllegalAccessException (see CLJ-2066). This will not be addressed in Clojure 1.9, but is easily worked around by type hinting the call target to avoid reflection. I expect this will be addressed in the next release; the changes are significant enough that it seemed too risky (for all other reflective calls) to change right before the release. On Friday, November 10, 2017 at 12:48:01 PM UTC-6, Didier wrote: > > Is Clojure 1.9 expected to support JDK9? Or is that support reserved for a > later version? > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
