App and boot classloaders have changed Java 9

[tobias]

The boot classloader used to be sun.misc.Launcher, but it has been renamed. This may impact any code that walks the classloader tree with the assumption that sun.misc.Launcher exists.

This will definitely cause any project that uses a dynapath less than 0.2.4 to fail to load, since it made that assumption. And any project that uses dynapath less than 0.2.5 may fail under Java 9 when AOT'd, and will get an exception when trying to modify a URLClassLoader as of Java 9-ea+148.

The app classloader is no longer a URLClassLoader, so any code that assumes it is will fail.

These dynapath issues affect:

• Leiningen transitively, via Bultitude and Pomegranate (Java 9 incompatibility technomancy/leiningen#2149)
• Pomegranate (Update to dynapath 0.2.4 to support Java 9 clj-commons/pomegranate#78)
• cider-nrepl (Update to dynapath 0.2.5 clojure-emacs/cider-nrepl#383)
• Midje (Update to dynapath 0.2.5 marick/Midje#378)
• All 1.x Immutant versions
• Boot (Update to dynapath 0.2.4 boot-clj/boot#528)
• Bultitude (Bultitude doesn't work under Java 9 Raynes/bultitude#30)
• puppetlabs/kitchensink (kitchensink build fails under Java 9 puppetlabs/clj-kitchensink#79)

The app classloader changes affect:

• Boot (Install/first-run fails on Java 9 with ClassCastException boot-clj/boot#525)
• Bultitude (Bultitude doesn't work under Java 9 Raynes/bultitude#30)
• puppetlabs/kitchensink (kitchensink build fails under Java 9 puppetlabs/clj-kitchensink#79)