I'm using Tomcat and after stopping my web application there's still a reference to the classloader instance of my web application.
With the consequence that a notable amount of memory (mostly related to static data) will not be freed. Sooner or later this results in an OutOfMemoryError.
I took a heap dump and I realized that its held by a JNI global reference which prevents that the classloader will be garbage collected.
My application does not use JNI. I am also not using the Apache Tomcat Native Library. I am using a Sun/Oracle JDK.
I'd like to track down the cause/origin of this global reference.
(My guess is that the JVM internally references the classloader - but why/where?).
Question:
- Which approaches/toolsets exists to achieve this?
UPDATE
It seems that bestsss is right and the JNI global references has been introduced by the jvm debug mode. This helped me out but it does not answer the question so I am still curious to get an answer to the question which might be helpful in the future.