Question
My JDK 9+181 Spring Boot 2.0.0.BUILD-SNAPSHOT CLI application displays this warning on startup:
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.springframework.cglib.core.ReflectUtils$1 (jar:file:/home/jan/src/fm-cli/target/fm-cli-0.1.0-SNAPSHOT.jar!/BOOT-INF/lib/spring-core-5.0.0.RELEASE.jar!/) to method java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain)
WARNING: Please consider reporting this to the maintainers of org.springframework.cglib.core.ReflectUtils$1
This is a console application, so I need to disable this warning -- how can I do that?
Note: This question asks the specific question of how to disable this warning triggered by Spring; it is not a duplicate of [JDK9: An illegal reflective access operation has occurred. org.python.core.PySystemState](https://stackoverflow.com/questions/46230413/jdk9-an- illegal-reflective-access-operation-has-occurred-org-python-core-pysys) which deals with a similar symptom in a different library.
Answer
In JDK 9+, add the following option to the JVM to disable the warning from Spring's use of CGLIB:
--add-opens java.base/java.lang=ALL-UNNAMED
for example:
java --add-opens java.base/java.lang=ALL-UNNAMED -jar target/*.jar
No need to report it; it's a known Spring bug.
This happens because the new JDK 9 module system detected an illegal access that will be disallowed sometime in the (near) future. You can read more about [the JDK 9 Module system here](https://docs.oracle.com/javase/9/migrate/toc.htm#JSMIG- GUID-2F61F3A9-0979-46A4-8B49-325BA0EE8B66).
Update :
A fix for this issue is available JDK 9+ with Spring 5.1+.
