Java 9: Illegal reflective access --------------------------------- Key: WFLY-10776 URL: https://issues.jboss.org/browse/WFLY-10776 Project: WildFly Issue Type: Bug Components: Management Environment: Fedora 26, x86_64 {code} $ java -version openjdk version "9.0.1" OpenJDK Runtime Environment (build 9.0.1+11) OpenJDK 64-Bit Server VM (build 9.0.1+11, mixed mode) {code} Reporter: Marek Kopecký Assignee: Stefan Guilhen I can see following warnings when I start EAP7.1.0.GA server with JDK9: {code} WARNING: Illegal reflective access by org.wildfly.security.manager.GetAccessibleDeclaredFieldAction (jar:file:/tmp/CR4/jboss-eap-7.1/modules/system/layers/base/org/wildfly/security/elytron-private/main/wildfly-elytron-1.1.7.Final-redhat-1.jar!/) to field java.security.AccessControlContext.context WARNING: Illegal reflective access by org.jboss.threads.ThreadLocalResetter$1 (jar:file:/tmp/CR4/jboss-eap-7.1/modules/system/layers/base/org/jboss/threads/main/jboss-threads-2.2.1.Final-redhat-1.jar!/) to field java.lang.Thread.threadLocals WARNING: Illegal reflective access by org.jboss.threads.ThreadLocalResetter$2 (jar:file:/tmp/CR4/jboss-eap-7.1/modules/system/layers/base/org/jboss/threads/main/jboss-threads-2.2.1.Final-redhat-1.jar!/) to field java.lang.Thread.inheritableThreadLocals WARNING: Illegal reflective access by org.xnio.nio.NioXnio$2 (jar:file:/tmp/CR4/jboss-eap-7.1/modules/system/layers/base/org/jboss/xnio/nio/main/xnio-nio-3.5.4.Final-redhat-1.jar!/) to constructor sun.nio.ch.EPollSelectorProvider() WARNING: Illegal reflective access by io.undertow.util.FlexBase64$1 (jar:file:/tmp/CR4/jboss-eap-7.1/modules/system/layers/base/io/undertow/core/main/undertow-core-1.4.18.Final-redhat-2.jar!/) to constructor java.lang.String(char[],boolean) {code} Oracle has stated that {quote} When deny becomes the default illegal-access mode then permit will likely remain supported for at least one release, so that developers can continue to migrate their code. The permit, warn, and debug modes will, over time, be removed, as will the --illegal-access option itself. {quote} http://openjdk.java.net/jeps/261#Relaxed-strong-encapsulation Not sure what all components are affected, I see at least Undertow and XNIO. Well, to be honest, I guess there will be more problems in the code which occurr in various situations...