How to Test if Your Tomcat Web Application Is Thread Safe

In the following, I want to show you how to test if your Tomcat web application is thread-safe. As an example application, I use Jenkins deployed on an Apache Tomcat 9.0.
To detect concurrency bugs during our tests we use vmlens. vmlens traces the test execution and analyzes the trace afterward. It detects deadlocks and race conditions during the test run.