LDEV-1218 Deployed did address this already, but there is still an issue that leads to zombie threads in the servlet engine.
What is a Zombie threads and how we do avoid this?
In case of a request timeout, we do a
for the thread of the Request coming from the servlet engine. what not only throws a "ThreadDeath" in the thread it also makes the thread unusable for further use (different depending on JVM). Problem is that tomcat reuses a thread that stopped because Lucee does not forward that ThreadDeath Error. We fixed this with LDEV-1218 Deployed but this needs an update of the lucee.jar. After the fix of LDEV-1218 Deployed we still saw an issue with that, somehow tomcat seems not really to care about a ThreadDeath and still use the thread. Java 8 also changed
So the best way to fix this, is never to "stop" a thread coming from Tomcat by opening our own threads.