The following code is emitted for a Java/Groovy build using Gradle v4.10.3 and using the Spock BDD testing framework, JDK 8 targeting JRE 8. The message says to report this.
I didn't find an open bug with this message – Towit, I'm reporting it.
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.codehaus.groovy.reflection.CachedClass (file:/scr/root/.caches/william/gradle/caches/modules-2/files-2.1/org.codehaus.groovy/groovy-all/2.4.15/5f71e0843ea6c949920f3219c6c961a3895e53c4/groovy-all-2.4.15-indy.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
Note: Creating bean classes for 2 type elements
warning: Implicitly compiled files were not subject to annotation processing.
Use -implicit to specify a policy for implicit compilation.