Get rid of warnings when OpenJDK is used

[wwalc]

[Comandeer]

openjdk 12.0.1:

Generating plugins sprite image
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.mozilla.javascript.MemberBox (file:/Users/comandeer/repos/ckeditor/ckeditor-presets/ckbuilder/2.3.2/ckbuilder.jar) to method sun.java2d.SunGraphics2D.drawImage(java.awt.Image,int,int,java.awt.image.ImageObserver)
WARNING: Please consider reporting this to the maintainers of org.mozilla.javascript.MemberBox
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

[wwalc]

Humm it looks like we'd need to wait for https://github.com/mozilla/rhino/issues/462 to be resolved.

[botic]

Ah, just ran into the same on Java 11:

     [java] WARNING: Illegal reflective access by org.mozilla.javascript.MemberBox (file:/Users/philipp/Code/ringojs/lib/ivy/rhino-1.7.12.jar) to method sun.nio.cs.UTF_8.newEncoder()
     [java] WARNING: Please consider reporting this to the maintainers of org.mozilla.javascript.MemberBox
     [java] WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
     [java] WARNING: All illegal access operations will be denied in a future release