For JRuby- the reflective access warnings with jdk > 8 are mainly fixed (providing you define JAVA_HOME). However for JRubyArt (PiCrate and propane) JOGL warnings remain for OpenGL sketches

For Debian linux, define JAVA_HOME in ~/.profile for ArchLinux and others define JAVA_HOME in ~/.bashrc. Windows and Mac users should do similar. Create a ~/.jruby.java_opts file with following content to fix JOGL reflective access warnings:-

--add-opens java.base/java.lang=ALL-UNNAMED
--add-opens java.desktop/java.awt=ALL-UNNAMED
--add-opens java.desktop/sun.awt=ALL-UNNAMED
--add-opens java.desktop/sun.java2d.opengl=ALL-UNNAMED

NB: ALL-UNNAMED is for legacy jar access, if we had named modules we could/should be more specific. Fortunately this will no be necessary, since JOGL-2.4.0 does not generate any warnings.