An illegal reflective access operation has occurred

[peterlobster]

I did a clean of Maven thru Homebrew and then installed mvnsh. When I call mvnsh I get this warning...

$mvnsh
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.thoughtworks.xstream.converters.collections.TreeMapConverter (file:/usr/local/Cellar/maven-shell/1.1.0/libexec/lib/mvnsh/xstream-1.4.4.jar) to field java.util.TreeMap.comparator
WARNING: Please consider reporting this to the maintainers of com.thoughtworks.xstream.converters.collections.TreeMapConverter
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
Sonatype Maven Shell (1.1.0,201304261627)

Type 'help' for more information.
-------------------------------------------------------------------------------------------------------------------------------------------

$mvnsh --illegal-access=warn
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.thoughtworks.xstream.converters.collections.TreeMapConverter (file:/usr/local/Cellar/maven-shell/1.1.0/libexec/lib/mvnsh/xstream-1.4.4.jar) to field java.util.TreeMap.comparator
WARNING: Please consider reporting this to the maintainers of com.thoughtworks.xstream.converters.collections.TreeMapConverter
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
org.sonatype.gshell.command.registry.NoSuchCommandException: --illegal-access=warn
	at org.sonatype.gshell.execute.CommandExecutorImpl.createAction(CommandExecutorImpl.java:129)
	at org.sonatype.gshell.execute.CommandExecutorImpl.execute(CommandExecutorImpl.java:144)
	at org.sonatype.gshell.execute.CommandExecutorImpl.execute(CommandExecutorImpl.java:117)
	at org.sonatype.gshell.shell.ShellImpl.execute(ShellImpl.java:224)
	at org.sonatype.gshell.MainSupport.boot(MainSupport.java:283)
	at org.sonatype.maven.shell.Main.main(Main.java:71)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.sonatype.maven.shell.launcher.Launcher.launch(Launcher.java:75)
	at org.sonatype.maven.shell.launcher.Launcher.run(Launcher.java:48)
	at org.sonatype.maven.shell.launcher.Launcher.main(Launcher.java:39)

WARNING: Abnormal JVM shutdown detected

$mvn -v
Apache Maven 3.6.0 (97c98ec64a1fdfee7767ce5ffb20918da4f719f3; 2018-10-24T11:41:47-07:00)
Maven home: /usr/local/Cellar/maven/3.6.0/libexec
Java version: 11.0.1, vendor: Oracle Corporation, runtime: /Library/Java/JavaVirtualMachines/openjdk-11.0.1.jdk/Contents/Home
Default locale: en_US, platform encoding: UTF-8
OS name: "mac os x", version: "10.13.6", arch: "x86_64", family: "mac"