This line is failing with Jake and not with 9-dev.
  Object r = web.executeScript("alist.toArray(iarr)");

I am attaching a standalone test that demonstrates the problem.

I am running the test with jake using the command:

JFX_JAKE=/home/ddhill/sb/jake/jfx/rt/

$JDK9_HOME/bin/java \
   -Xpatch:$JFX_JAKE/build/testing/modules \
   -Djava.library.path=$JFX_JAKE/build/sdk/lib/amd64 \
   -cp Tests.jar ToArrayTestFailure



The affected junit test is:

test.javafx.scene.web.JavaScriptBridgeTest > testBridgeExplicitOverloading FAILED
    java.lang.AssertionError: expected same:<[Ljava.lang.Integer;@cdfd500> was not:<undefined>
        at org.junit.Assert.fail(Assert.java:91)
        at org.junit.Assert.failNotSame(Assert.java:639)
        at org.junit.Assert.assertSame(Assert.java:578)
        at org.junit.Assert.assertSame(Assert.java:591)
        at test.javafx.scene.web.JavaScriptBridgeTest.lambda$testBridgeExplicitOverloading$108(JavaScriptBridgeTest.java:419)