Java Management Extensions (JMX) is a technology that permits applications to expose properties and operations through managed beans, or "MBeans". Tomcat supports JMX and provides numerous MBeans to a consumer program, such as jconsole, that expose useful properties and operations. But in order to access Tomcat's MBeans we must configure Tomcat to expose the MBeans to consumers.
When we copy a WAR file to the application base directory of Apache Tomcat we usually expect the web application to be deployed. In other words, we expect the web site to be immediately available on the World Wide Web. However, this doesn't always have to be the case. The autoDeply attribute on the Host element determines if the web application will be available for access on the internet.