lein lux build doesn't work (JDK9)

[denkspuren]

I tried to run the "hello world" example as described in chapter 1 of the Lux book. Running lein terminated with a java.lang.ClassCastException. I guess it's because I'm using JDK9 on my computer.

C:\Users\Dominikus\Lux\myproject>lein lux build
Retrieving com/github/luxlang/lein-luxc/0.5.0/lein-luxc-0.5.0.pom from central
Retrieving org/clojure/clojure/1.6.0/clojure-1.6.0.pom from central
Retrieving com/github/luxlang/luxc-jvm/0.5.0/luxc-jvm-0.5.0.pom from central
Retrieving org/clojure/core.match/0.2.1/core.match-0.2.1.pom from central
Retrieving org/clojure/pom.contrib/0.1.2/pom.contrib-0.1.2.pom from central
Retrieving org/clojure/clojure/1.4.0/clojure-1.4.0.pom from central
Retrieving org/sonatype/oss/oss-parent/5/oss-parent-5.pom from central
Retrieving org/ow2/asm/asm-all/5.0.3/asm-all-5.0.3.pom from central
Retrieving org/ow2/asm/asm-parent/5.0.3/asm-parent-5.0.3.pom from central
Retrieving com/github/luxlang/stdlib/0.5.0/stdlib-0.5.0.pom from central
Retrieving org/clojure/clojure/1.6.0/clojure-1.6.0.jar from central
Retrieving org/clojure/core.match/0.2.1/core.match-0.2.1.jar from central
Retrieving org/ow2/asm/asm-all/5.0.3/asm-all-5.0.3.jar from central
Retrieving com/github/luxlang/luxc-jvm/0.5.0/luxc-jvm-0.5.0.jar from central
Retrieving com/github/luxlang/lein-luxc/0.5.0/lein-luxc-0.5.0.jar from central
Retrieving com/github/luxlang/stdlib/0.5.0/stdlib-0.5.0.jar from central
java.lang.ClassCastException: java.base/jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to java.base/java.net.URLClassLoader
 at leiningen.lux.utils$all_jars_in_classloader.invokeStatic (utils.clj:30)
    leiningen.lux.utils$all_jars_in_classloader.invoke (utils.clj:29)
    leiningen.lux.utils$compile_path.invokeStatic (utils.clj:66)
    leiningen.lux.utils$compile_path.invoke (utils.clj:66)
    leiningen.lux.builder$build.invokeStatic (builder.clj:8)
    leiningen.lux.builder$build.invoke (builder.clj:6)
    leiningen.lux$lux.invokeStatic (lux.clj:12)
    leiningen.lux$lux.doInvoke (lux.clj:10)
    clojure.lang.RestFn.invoke (RestFn.java:423)
    clojure.lang.Var.invoke (Var.java:383)
    clojure.lang.AFn.applyToHelper (AFn.java:156)
    clojure.lang.Var.applyTo (Var.java:700)
    clojure.core$apply.invokeStatic (core.clj:648)
    clojure.core$apply.invoke (core.clj:641)
    leiningen.core.main$partial_task$fn__5932.doInvoke (main.clj:272)
    clojure.lang.RestFn.applyTo (RestFn.java:139)
    clojure.lang.AFunction$1.doInvoke (AFunction.java:29)
    clojure.lang.RestFn.applyTo (RestFn.java:137)
    clojure.core$apply.invokeStatic (core.clj:648)
    clojure.core$apply.invoke (core.clj:641)
    leiningen.core.main$apply_task.invokeStatic (main.clj:322)
    leiningen.core.main$apply_task.invoke (main.clj:308)
    leiningen.core.main$resolve_and_apply.invokeStatic (main.clj:328)
    leiningen.core.main$resolve_and_apply.invoke (main.clj:324)
    leiningen.core.main$_main$fn__5998.invoke (main.clj:401)
    leiningen.core.main$_main.invokeStatic (main.clj:394)
    leiningen.core.main$_main.doInvoke (main.clj:391)
    clojure.lang.RestFn.invoke (RestFn.java:421)
    clojure.lang.Var.invoke (Var.java:383)
    clojure.lang.AFn.applyToHelper (AFn.java:156)
    clojure.lang.Var.applyTo (Var.java:700)
    clojure.core$apply.invokeStatic (core.clj:646)
    clojure.main$main_opt.invokeStatic (main.clj:314)
    clojure.main$main_opt.invoke (main.clj:310)
    clojure.main$main.invokeStatic (main.clj:421)
    clojure.main$main.doInvoke (main.clj:384)
    clojure.lang.RestFn.invoke (RestFn.java:457)
    clojure.lang.Var.invoke (Var.java:394)
    clojure.lang.AFn.applyToHelper (AFn.java:165)
    clojure.lang.Var.applyTo (Var.java:700)
    clojure.main.main (main.java:37)

[denkspuren]

Did some research: The java.net.URLClassLoader is used at three places in the lux code base. It's a known problem under Java 9, as a quick search on Google reveals.

"The app classloader is no longer a URLClassLoader, so any code that assumes it is will fail.", see e.g. Source

There are "New Class Loader Implementations" says Oracle.