Hi,

It's long overdue, but the status quo is not really nice. Running Groovy on Java 9+ gives warnings like this:

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.codehaus.groovy.vmplugin.v7.Java7$1 (file:/tmp/groovy-2.5.3/target/groovy-2.5.3/lib/groovy-2.5.3.jar) to constructor java.lang.invoke.MethodHandles$Lookup(java.lang.Class,int)
WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.vmplugin.v7.Java7$1

Or

WARNING: Illegal reflective access by org.codehaus.groovy.reflection.CachedClass (file:/home/tcagent1/agent/work/668602365d1521fc/subprojects/ivy/build/integ%20test/lib/groovy-all-2.4.12.jar) to method java.lang.Object.finalize()
WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.reflection.CachedClass
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

I know it's hard to get rid of those, but we have to do something. Unfortunately I don't have the expertise here...