When I try to build a job with OpenJ9 for Java 12, I get a SecurityException in the remote executor before the maven execution actually starts:

[IPACT_Java12] $ /var/local/jenkins/tools/hudson.model.JDK/JDK12_OpenJ9/jdk-12+33/bin/java -Duser.home=/var/local/jenkins -cp /var/local/jenkins/plugins/maven-plugin/WEB-INF/lib/maven33-agent-1.12.jar:/var/local/jenkins/tools/hudson.tasks.Maven_MavenInstallation/Maven3/boot/plexus-classworlds-2.5.2.jar:/var/local/jenkins/tools/hudson.tasks.Maven_MavenInstallation/Maven3/conf/logging jenkins.maven3.agent.Maven33Main /var/local/jenkins/tools/hudson.tasks.Maven_MavenInstallation/Maven3 /var/lib/tomcat8/webapps/jenkins/WEB-INF/lib/remoting-3.29.jar /var/local/jenkins/plugins/maven-plugin/WEB-INF/lib/maven33-interceptor-1.12.jar /var/local/jenkins/plugins/maven-plugin/WEB-INF/lib/maven3-interceptor-commons-1.12.jar 34243
<===[JENKINS REMOTING CAPACITY]===>Exception in thread "main" java.lang.reflect.InvocationTargetException
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:567)
at jenkins.maven3.agent.Maven33Main.main(Maven33Main.java:135)
at jenkins.maven3.agent.Maven33Main.main(Maven33Main.java:64)
Caused by: java.lang.SecurityException: Signers of 'hudson.remoting.$Proxy1' do not match signers of other classes in package
at java.base/java.lang.ClassLoader.checkPackageSigners(ClassLoader.java:556)
at java.base/java.lang.ClassLoader.defineClassInternal(ClassLoader.java:470)
at java.base/java.lang.Access.defineClass(Access.java:240)
at java.base/java.lang.reflect.Proxy$ProxyBuilder.defineProxyClass(Proxy.java:537)
at java.base/java.lang.reflect.Proxy$ProxyBuilder.build(Proxy.java:646)
at java.base/java.lang.reflect.Proxy.lambda$getProxyConstructor$1(Proxy.java:425)
at java.lang.reflect.Proxy$$Lambda$23.00000000404E6040.apply(Unknown Source)
at java.base/jdk.internal.loader.AbstractClassLoaderValue$Memoizer.get(AbstractClassLoaderValue.java:329)
at java.base/jdk.internal.loader.AbstractClassLoaderValue.computeIfAbsent(AbstractClassLoaderValue.java:205)
at java.base/java.lang.reflect.Proxy.getProxyConstructor(Proxy.java:423)
at java.base/java.lang.reflect.Proxy.newProxyInstance(Proxy.java:1004)
at hudson.remoting.RemoteInvocationHandler.wrap(RemoteInvocationHandler.java:167)
at hudson.remoting.Channel.<init>(Channel.java:541)
at hudson.remoting.ChannelBuilder.build(ChannelBuilder.java:360)
at hudson.remoting.Launcher.main(Launcher.java:743)
at hudson.remoting.Launcher.main(Launcher.java:724)
at hudson.remoting.Launcher.main(Launcher.java:715)
at hudson.remoting.Launcher.main(Launcher.java:711)
... 6 more
Set build name.
New build name is '#5 (11.9.6)'
ERROR: Processing failed due to a bug in the code. Please report this to the issue tracker (https://jenkins.io/redirect/report-an-issue).

I use this version of OpenJ9 from adoptopenjdk.net:

https://github.com/AdoptOpenJDK/openjdk12-binaries/releases/download/jdk-12%2B33_openj9-0.13.0/OpenJDK12U-jdk_x64_linux_openj9_12_33_openj9-0.13.0.tar.gz

When I use a nightly build of the Hotspot JVM for Java 12, everything works fine.