Article - CS405220
"WARNING: Illegal reflective access by com.thingworx.extensibility.resources.JarResourceCollection" is logged in Tomcat when importing a Java extension in ThingWorx
Modified: 21-Jul-2025
Applies To
- ThingWorx Platform 9.3
Description
- "illegal reflective access operation" warning in Tomcat logs when importing a Java extension
- The issue is observed in all version of ThingWorx when using recent version of Java
- Full message from Tomcat stdout:
WARNING: An illegal reflective access operation has occurred WARNING: Illegal reflective access by com.thingworx.extensibility.resources.JarResourceCollection (file:/C:/TWX/Thingworx_9.3.12/apache-tomcat/webapps/Thingworx/WEB-INF/lib/thingworx-platform-common-9.3.12-b2058.jar) to method java.net.URLClassLoader.addURL(java.net.URL) WARNING: Please consider reporting this to the maintainers of com.thingworx.extensibility.resources.JarResourceCollection 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
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