When multiple Tomcat containers are started in the same JVM there is a conflict on the JMX beans they create. Components get prefixed with the name of the Engine they run in, and if the different StandardEngine objects have the same name, there will be one JMX bean yet two actual underlying components. During a shutdown, Tomcat will attempt to unregister the same JMX bean multiple times. Simple workaround is to give the Engine a unique name in the JVM